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Abstract:

An organic semiconductor material is provided. The organic semiconductor
material includes a polyacene derivative expressed by the following
general formula (1):
##STR00001##
where each of R1 to R10 may be independently the same
substituents or different substituents but all of R1, R4,
R5, R6, R9 and R10 may never be hydrogen atoms at the
same time, and where each of R1 to R10 is at least one kind of
substituent selected from the group consisting of an aliphatic
hydrocarbon group having a substituent and of which number of carbon
atoms ranges of from 1 to 20, an aromatic hydrocarbon group having a
substituent, a complex aromatic group having a substituent, a carboxyl
group, a hydride, an ester group, a cyano group, a hydroxyl group, a
halogen atom and a hydrogen atom. The organic semiconductor material can
be dissolved into an organic solvent at low temperature (for example,
room temperature) and is suitable for use with a coating process.

Claims:

1. An organic semiconductor material consisting of a polyacene derivative
expressed by the following general formula (2): ##STR00043## wherein n is
an integer ranging of from 0 to 20;wherein each of R1, R2,
R3, R4, R5, R6, R7 and R8 may be
independently the same substituents or different substituents, when n is
greater than 2, a plurality of R5 existing the general formula (2)
may be the same substituents or different substituents, a plurality of
R8 existing in the general formula (2) may be the same substituents
or different substituents and R1, R4, R5 and R8 may
never be hydrogen atoms at the same time; andwherein each of R1,
R2, R3, R4, R5, R6, R7 and R8 in the
(condition-B1) is at least one kind of substituent selected from the
group consisting of an aliphatic hydrocarbon group having a substituent
and of which number of carbon atoms ranges from 1 to 20, an aromatic
hydrocarbon group having a substituent, a complex aromatic group having a
substituent, a carboxyl group, a hydride, an ester group, a cyano group,
a hydroxyl group, a thiocarboxyl group, a dithiocarboxyl group, a
sulfonic acid group, a sulfinic acid group, a sulfenic acid group, a
sulfonyl group, a sulfinyl group, an acyl halide group, a carbamoyl
group, a hydrazide group, an imide group, an amide group, an amidino
group, an isocyano group, a cyanic acid ester group, an isocyanic acid
ester group, a thiocyanic acid ester group, an isothiocyanic acid ester
group, a formyl group, a thioformyl group, an acyl group, a thiol group,
an amino group, an imino group, a hydrazino group, an alkoxy group, an
arlyoxy group, an ether group, a sulfide group, a disulfide group, a
silyl group, a germyl group, a stannyl group, a phosphino group, a boryl
group, a halogen atom and a hydrogen atom.

2. An organic semiconductor material according to claim 1, wherein each of
R1r R2, R3, R4, R5, R6, R7 and R8
is at least one kind of substituent selected from the group consisting of
an aliphatic hydrocarbon group having a substituent and of which number
of carbon atoms ranges from 1 to 20, an aromatic hydrocarbon group having
a substituent, a complex aromatic group having a substituent, a carboxyl
group, a hydride, an ester group, a cyano group, a hydroxyl group, a
halogen atom and a hydrogen atom.

3. An organic semiconductor material according to claim 2, wherein n is
greater than 5 and a substituent at a part of an acene bone is an alkyl
group having greater than 3 carbon atoms.

4. An organic semiconductor thin film made of an organic semiconductor
material according to claim 4, said organic semiconductor thin film
having crystallinity.

5. An organic semiconductor thin film according to claim 4, wherein a
substituent at a part of an acene bone in the organic semiconductor
material is an alkyl group having greater than 3 carbon atoms.

6. An organic semiconductor thin film according to claim 5, having a stack
structure.

7. An organic semiconductor thin film made of an organic semiconductor
material according to claim 2, said organic semiconductor thin film
having crystallinity.

8. An organic semiconductor thin film according to claim 7, wherein a
substituent at a part of an acene bone in the organic semiconductor
material is an alkyl group of which number of carbon atoms is greater
than 3.

9. An organic semiconductor thin film according to claim 8, having a stack
structure.

10. An organic semiconductor device including an organic semiconductor
thin film made of an organic semiconductor material according to claim 1,
said organic semiconductor thin film having crystallinity.

11. An organic semiconductor device according to claim 10, wherein a
substituent at a part of an acene bone in the organic semiconductor
material is an alkyl having greater than 3 carbon atoms.

12. An organic semiconductor device according to claim 11, wherein said
organic semiconductor thin film has a stack structure.

13. An organic semiconductor device including an organic semiconductor
thin film made of an organic semiconductor material according to claim 2,
said organic semiconductor thin film having crystallinity.

14. An organic semiconductor device according to claim 13, wherein a
substituent at a part of an acene bone in the organic semiconductor
material is an alkyl having greater than 3 carbon atoms.

15. An organic semiconductor device according to claim 14, wherein said
organic semiconductor thin film has a stack structure.

16. An organic semiconductor device according to claim 10, wherein said
organic semiconductor device comprises a source/drain electrode, a
channel forming region sandwiched between a source/drain electrode and a
source/drain electrode, a gate insulating layer and a gate electrode
opposed to said channel forming region through said gate insulating
layer, said channel forming region being composed of the organic
semiconductor thin film.

17. An organic semiconductor device according to claim 11, wherein said
organic semiconductor device comprises a source/drain electrode, a
channel forming region sandwiched between a source/drain electrode and a
source/drain electrode, a gate insulating layer and a gate electrode
opposed to said channel forming region through said gate insulating
layer, said channel forming region being composed of the organic
semiconductor thin film.

18. An organic semiconductor device according to claim 12, wherein said
organic semiconductor device comprises a source/drain electrode, a
channel forming region sandwiched between a source/drain electrode and a
source/drain electrode, a gate insulating layer and a gate electrode
opposed to said channel forming region through said gate insulating
layer, said channel forming region being composed of the organic
semiconductor thin film.

19. An organic semiconductor device according to claim 13, wherein said
organic semiconductor device comprises a source/drain electrode, a
channel forming region sandwiched between a source/drain electrode and a
source/drain electrode, a gate insulating layer and a gate electrode
opposed to said channel forming region through said gate insulating
layer, said channel forming region being composed of the organic
semiconductor thin film.

20. An organic semiconductor device according to claim 14, wherein said
organic semiconductor device comprises a source/drain electrode, a
channel forming region sandwiched between a source/drain electrode and a
source/drain electrode, a gate insulating layer and a gate electrode
opposed to said channel forming region through said gate insulating
layer, said channel forming region being composed of the organic
semiconductor thin film.

21. An organic semiconductor device according to claim 15, wherein said
organic semiconductor device comprises a source/drain electrode, a
channel forming region sandwiched between a source/drain electrode and a
source/drain electrode, a gate insulating layer and a gate electrode
opposed to said channel forming region through said gate insulating
layer, said channel forming region being composed of the organic
semiconductor thin film.

Description:

CROSS REFERENCES TO RELATED APPLICATIONS

[0001]The present application is a divisional of U.S. patent application
Ser. No. 11/421,295, filed on May 31, 2006 and claims priority to
Japanese Patent Application JP 2005-161301 filed in the Japanese Patent
Office on Jun. 1, 2005 and Japanese Patent Application JP 2006-052927
filed in the Japanese Patent Office on Feb. 28, 2006 the entire contents
of which being incorporated herein by reference.

[0003]Semiconductor devices using organic semiconductor materials are able
to decrease a manufacturing cost as compared with related-art
semiconductor devices using inorganic semiconductor materials such as Si
(silicon) and they can be also expected as semiconductor devices with
flexibility as well. Then, various kinds of organic semiconductor
materials such as polythiophene and rubrene are now under studies as the
organic semiconductor materials, and it has been reported that a
transistor including a channel forming region made of these organic
semiconductor materials may have mobility of substantially the same as
that of a transistor including a channel forming region made of amorphous
silicon (see APL Vol. 80, No. 6, 1088-1090 (2002), for example).

[0004]When the channel forming region is made by these organic
semiconductor materials, since these organic semiconductor materials are
difficult to be dissolved into an organic solvent and the application of
a coating process to these organic semiconductor materials is difficult
and it is customary that semiconductor films are exclusively formed by a
vacuum evaporation coating method. On the other hand, a simple alkyl
chain and other substituents are introduced into these organic
semiconductor materials to cause an organic solvent to have affinity so
that these organic semiconductor materials can be dissolved into the
organic solvent. In actual practice, poly-3-hexylthiophene (P3HT) can be
dissolved into an organic solvent such as chloroform and toluene and it
has been reported that a channel forming region could be formed by a
coating process such as a spin coating method (see APL 69 (26), 4108-4110
(1996) for example).

[0005]On the other hand, a polyacene compound, which is a condensed
polycyclic compound, is a molecule having a π electron conjugated
system similarly to polyacetylene and polyphenylene. In addition, the
polyacene compound has a small bandgap as compared with polyacetylene and
the like from theoretically and it is a compound which can be expected to
have excellent functions as an organic semiconductor material.
Substituents that have been introduced into the polyacene compound can be
used so that it can be coupled to their molecules and a functional group
on the surface of an insulating film. Also, these substituents can be
used to control a distance, a position and an arrangement of an acene
bone and patterning and the like. The polyacene compound is a compound in
which benzene rings are coupled in a straight line fashion. A polyacene
compound without substituents has properties in which it becomes
difficult to be dissolved into an organic solvent in accordance with the
increase of the number of the benzene rings. In particular, a polyacene
compound greater than pentacene having five benzene rings coupled loses
its solubility to almost all of organic solvents and it is very difficult
to form a uniform film based on a suitable method such as the spin
coating method. Even if a uniform film can be formed by using such
polyacene compound based on the spin coating method and the like, it is
unavoidable that organic solvents and temperature conditions available in
the spin coating method and the like will be extremely limited (for
example, trichlorobenzene and 60 to 180° C.). Also, it is widely
known that stability of the polyacene compound is lowered as the number
of benzene rings is increased and that pentacene is oxidized by oxygen in
the air. That is, pentacene is poor in oxidation resistance.

[0006]2,3,9,10-tetramethylpentacene was reported as an example in which
substituents are introduced into a polyacene compound (see Wudl and Bao,
Adv. Mater Vol. 15, No. 3 (1090-1093), 2003). However, this
2,3,9,10-tetramethylpentacene can be slightly dissolved into warmed
1,2-dichlorobenzene, and hence a channel forming region constructing an
FET (field-effect transistor) is formed by a vacuum evaporation coating
method.

[0007]Also, Japanese Published Patent Application No. 2004-256532 has
described that 2,3,9,10-tetramethylpentacene and 2,3-dimethylpentacene
are dissolved into 1,2-dichlorobenzene. However, they can be dissolved
into 1,2-dichlorobenzene at 120° C. but the fact that they are
dissolved into 1,2-dichlorobenzene at room temperature is not described
in the above Japanese Published Patent Application 2004-256532.

[0008]J. Am. Chem. Soc. 124, 8812-8813 (2002) has reported a technology in
which a substituent, which is capable of carrying out thermal reversible
reaction, is introduced into pentacene to prepare a solution in the
pentacene precursor state with high solubility relative to an organic
solvent, this solution is coated on the substrate and heated, thereby
resulting in a pentacene thin film being formed on the substrate.

[0009]Also, compounds in which substituents are introduced into pentacene
are known from a long ago and D. R. Maulding et al. has reported
syntheses of several pentacene derivatives in Journal of Organic
Chemistry, Vol. 34, No. 6, 1734-1736 (1969). Also, in recent years,
Takahashi et al. and Anthony et al. have reported many pentacene
derivatives. For example, refer to Organic Letters Vol. 6, No. 19,
3325-3328 (2004) and Organic Letters Vol. 4, No. 1, 15-18 (2002).

[0010]As described above, although the polyacene compound is a compound
which can be expected to exhibit excellent functions as an organic
semiconductor material, the polyacene compound is difficult to be
dissolved at low temperature (for example, room temperature) and which is
therefore not suitable for use with a coating process such as a spin
coating method.

SUMMARY

[0011]In view of the aforesaid aspects, the present application intends to
provide an organic semiconductor material which can be dissolved into an
organic solvent at low temperature (for example, room temperature) and
which is made of a polyacene derivative suitable for use with a coating
process.

[0012]Further, the present application intends to provide an organic
semiconductor thin film and an organic semiconductor device based on the
above organic semiconductor material.

[0013]According to a first embodiment, there is provided an organic
semiconductor material consisting of a polyacene derivative expressed by
the following general formula (1), each of R1, R2, R3,
R4, R5, R6, R7, R8, R9 and R10 in the
general formula (1) satisfying the following (condition-A1) and
(condition-A2):

##STR00002##

(Condition-A1)

[0014]R1, R2, R3, R4, R5, R6, R7,
R8, R9 and R10 may be independently the same substituents
or different substituents but all of R1, R4, R5, R6
and R10 may never be hydrogen atoms at the same time. (Condition-A2)
each of R1, R2, R3, R4, R5, R6, R7,
R8, R9 and R10 is at least one kind of substituent
selected from a substituent family consisting of an aliphatic hydrocarbon
group which has substituents or no substituents and of which number of
carbon atoms ranges from 1 to 20, an aromatic hydrocarbon group, which
has substituents or no substituents, a complex aromatic group which has
substituents or no substituents, a carboxyl group, a hydride, an ester
group, a cyano group, a hydroxyl group, a thiocarboxyl group, a
dithiocarboxyl group, a sulfonic acid group, a sulfinic acid group, a
sulfenic acid group, a sulfonyl group, a sulfinyl group, an acyl halide
group, a carbamoyl group, a hydrazide group, an imide group, an amide
group, an amidino group, an isocyano group, a cyanic acid ester group, an
isocyanic acid ester group, a thiocyanic acid ester group, an
isothiocyanic acid ester group, a formyl group, a thioformyl group, an
acyl group, a thiol group, an amino group, an imino group, a hydrazino
group, an alkoxy group, an arlyoxy group, an ether group, a sulfide
group, a disulfide group, a silyl group, a germyl group, a stannyl group,
a phosphino group, a boryl group, a halogen atom and a hydrogen atom.

[0015]In the organic semiconductor material according to the first
embodiment, it is preferable that each of R1, R2, R3,
R4, R5, R6, R7, R8, R9 and R10 should
be at least one kind of substituent selected from a substituent family
consisting of an aliphatic hydrocarbon group having a substituent and of
which number of carbon atoms ranges from 1 to 20, an aromatic hydrocarbon
group having a substituent, a complex aromatic group, a carboxyl group, a
hydride, an ester group, a cyano group, a hydroxyl group, a halogen atom
and a hydrogen atom. For convenience sake of explanation, the
above-mentioned aspect will hereinafter be referred to as an "organic
semiconductor material according to the aspect 1A".

[0016]According to a second embodiment, there is provided an organic
semiconductor material consisting of a polyacene derivative expressed by
the following general formula (2) [where n is an integer ranging of from
0 to 20], each of R1, R2, R3, R4, R5, R6,
R7 and R8 satisfying the following (condition-B1) and
(condition-B2).

##STR00003##

(Condition-B1)

[0017]R1, R2, R3, R4, R5, R6, R7 and
R8 may be independently the same substituents or different
substituents, when n is greater than 2, a plurality of R5 existing
the general formula (2) may be the same substituents or different
substituents, a plurality of R8 existing in the general formula (2) may
be the same substituents or different substituents and R1, R4,
R5 and R8 may never be hydrogen atoms at the same time.

(Condition-B2)

[0018]Each of R1, R2, R3, R4, R5, R6,
R7 and R8 in the (condition-B1) is at least one kind of
substituent selected from a substituent family consisting of an aliphatic
hydrocarbon group which has substituents or no substituents and of which
number of carbon atoms ranges from 1 to 20, an aromatic hydrocarbon group
which has substituents or no substituents, a complex aromatic group which
has substituents or no substituents, a carboxyl group, a hydride, an
ester group, a cyano group, a hydroxyl group, a thiocarboxyl group, a
dithiocarboxyl group, a sulfonic acid group, a sulfinic acid group, a
sulfenic acid group, a sulfonyl group, a sulfinyl group, an acyl halide
group, a carbamoyl group, a hydrazide group, an imide group, an amide
group, an amidino group, an isocyano group, a cyanic acid ester group, an
isocyanic acid ester group, a thiocyanic acid ester group, an
isothiocyanic acid ester group, a formyl group, a thioformyl group, an
acyl group, a thiol group, an amino group, an imino group, a hydrazino
group, an alkoxy group, an arlyoxy group, an ether group, a sulfide
group, a disulfide group, a silyl group, a germyl group, a stannyl group,
a phosphino group, a boryl group, a halogen atom and a hydrogen atom.

[0019]In the organic semiconductor material according to the second
embodiment, it is preferable that each of R1, R2, R3,
R4, R5, R6, R7 and R8 should be at least one
kind of a substituent selected from a substituent family consisting of an
aliphatic hydrocarbon group which has substituents or no substituents and
of which number of carbon atoms ranges from 1 to 20, an aromatic
hydrocarbon group which has substituents or no substituents, a complex
aromatic group which has substituents or no substituents, a carboxyl
group, a hydride, an ester group, a cyano group, a hydroxyl group, a
halogen atom and a hydrogen atom. For convenience sake of explanation,
the above-mentioned aspect will hereinafter be referred to as an "organic
semiconductor material according to the aspect 2A".

[0020]In the organic semiconductor materials according to the first
embodiment, the aspect 1A, the second embodiment or the aspect 2A, when a
substituent is an aliphatic hydrocarbon group, an alkyl group, an alkenyl
group and an alkynyl group can be enumerated as substituents
specifically.

[0021]Also, in the (condition-A2) in the organic semiconductor materials
according to the first aspect and the aspect 1A of the present invention
and in the (condition-B2) in the organic semiconductor materials
according to the second aspect and the aspect 2A of the present
invention, R1 to R10 or R1 to R8 are at least one
kind of substituent selected from the substituent family and this
substituent may include a substituent containing more than one kind of
substituents properly selected from the substituent family.

[0022]In the organic semiconductor material according to the first
embodiment, Rm and Rm' (m and m' are integers ranging of from 1
to 10 and m≠m') may be cross-linked with each other to form a
saturated ring or an unsaturated ring (structure including a double bond
or a tripe bond) of which number of carbon atoms lies in a range of from
4 to 20. An example in which a saturated ring of which number of carbon
atoms is 4 is formed by crosslinking, an example in which a saturated
ring of which number of carbon atoms is 5 is formed by cross-linking, an
example in which an unsaturated ring of which number of carbon atoms is 4
is formed by crosslinking and an example in which an unsaturated ring of
which number of carbon atoms is 5 is formed by crosslinking are shown as
follows.

##STR00004##

[0023]Also, in the organic semiconductor material according to the aspect
1A, when R1 to R10 are the aliphatic hydrocarbon groups, a
carboxyl group, a hydride, an ester group, a cyano group, a hydroxyl
group and a halogen atom may be bonded to a terminal of or somewhere of
this aliphatic hydrocarbon group in the branched state. R2 and
R3 may be crosslinked to form a saturated ring or unsaturated ring
of which number of carbon atoms lies in a range of from 4 to 20. R7
and R8 may be crosslinked to form a saturated ring or unsaturated
ring of which number of carbon atoms lies in a range of from 4 to 20.

[0024]In the organic semiconductor material according to the second
embodiment, Rm and Rm' (m and m' are integers ranging of from 1
to 8 and m≠m') may be crosslinked to form a saturated ring or
unsaturated ring (structure including a double bond and a triple bond) of
which number of carbon atoms lies in a range of from 4 to 20. Further,
when n is greater than 2, a plurality of R5 existing in the general
formula (2) may be crosslinked with each other. Also, a plurality of
R8 existing in the general formula (2) may be crosslinked with each
other.

[0025]Also, in the organic semiconductor material according to the aspect
2A, when R1 to R8 are the aliphatic hydrocarbon groups, a
carboxyl group, a hydride, an ester group, a cyano group, a hydroxyl
group and a halogen atom may be bonded to a terminal of or somewhere of
this aliphatic hydrocarbon group in the branched state. R2 and
R3 may be crosslinked to form a saturated ring or unsaturated ring
of which number of carbon atoms lies in a range of from 4 to 20. R6
and R7 may be crosslinked to form a saturated ring or an unsaturated
ring of which number of carbon atoms lies in a range of from 4 to 20.
Further, when n is greater than 2, a plurality of R5 existing in the
general formula (2) may be crosslinked with each other. Also, a plurality
of R8 existing in the general formula (2) may be crosslinked with
each other.

[0026]The (condition-A2) in the organic semiconductor material according
to the first embodiment is the condition identical to the (condition-B2)
in the organic semiconductor material according to the second embodiment.
In the (condition-A2) and the (condition-B2), each of R1 to R10
and R8 is at least one kind of a substituent selected from a
substituent family consisting of 45 kinds in total. Accordingly,
theoretically, 4510 combinations exist at maximum as combinations of
(R1, R2, R3, R4, R5, R6, R7, R8,
R9, R10), and any combinations may be used so long as it can
satisfy the (condition-A1). Also, in the organic semiconductor material
according to the second embodiment, 45.sup.(6+2n) combinations exist at
maximum as the combinations of (R1, R2, R3, R4,
R5, R6, R7, R8) theoretically, and any combination
may be used so long as it can satisfy the (condition-B1).

[0027]Also, the substituent family in the organic semiconductor material
according to the aspect 1A is identical to that in the organic
semiconductor material according to the aspect 2A. Then, each of R1
to R10 and R1 to R8 is at least one kind of a substituent
selected from a substituent family consisting of 10 kinds of substituents
in total. Accordingly, in the organic semiconductor material according to
the aspect 1A of the present invention, 1010 combinations exist at
maximum as the combinations of (R1, R2, R3, R4,
R5, R6, R7, R8, R9, R10) theoretically, and
any combination may be used so long as it can satisfy the (condition-A1).
Also, in the organic semiconductor material according to the aspect 2A of
the present invention, 10.sup.(6+2n) combinations exist at maximum as the
combinations of (R1, R2, R3, R4, R5, R6,
R7, R8) theoretically, and any combination may be used so long
as it can satisfy the (condition-B1).

[0028]In the organic semiconductor material according to the first
embodiment or the aspect 1A, it is preferable that a substituent at a
part of an acene bone should be an alkyl group of which number of carbon
atoms is greater than 3 from a standpoint of improving its solubility
relative to an organic solvent more. Also, in the organic semiconductor
material according to the second embodiment or the aspect 2A, it is
preferable that n should be greater than 3 and that a substituent at a
part of an acene bone should be an alkyl group of which number of carbon
atom is greater than 3 from a standpoint of improving its solubility
relative to an organic solvent more. The substituent at a part of the
acene bond may be, specifically, any one of substituents within R1
to R10 (the first aspect or the aspect 1A of the present invention)
or R1 to R8 (the second aspect or the aspect 2A of the present
invention). Alternatively, the cases in which all of R to R8 (the
second aspect or the aspect 2A of the present invention) are the alkyl
group of which number of carbon atoms is greater than 3 may be included.
In the research in which anthracene having a certain degree of solubility
relative to an organic solvent and an anthracene derivative are compared
with each other, the fact that any one of the anthracene and the
anthracene derivative having a long alkyl chain is advantageous from a
solubility standpoint is suggested in a doctor's thesis "Synthesis and
Application of Condensed Polycyclic Compounds having Functionality"
(2003), written by Masanori Kitamura, Hokkaido University. Having made
further examinations by using a pentacene and a pentacene derivative
which is difficult to be solved into an organic solvent, the inventors of
the present application understood that lengths rather than the ratios of
the substituents (R1 to R10 and R1 to R8) in the
acene bone considerably affect solubility relative to the organic
solvent. In particular, improvement of solubility in the polyacene
derivative into which the alkyl group was introduced as the substituent
is more remarkable in an alkyl group of which number of carbon atoms is
greater than 3 (alkyl group having a length longer than that of a propyl
group). It was clarified that, although an ethyl group used as a
substituent are able to achieve sufficient effects relative to
improvements of solubility, the kind of the organic solvent and the
temperature at which it can be dissolved into the organic solvent are
limited to ranges narrower than that of the alkyl group having a length
longer than that of a propyl group.

[0029]An organic semiconductor material according to the third embodiment
consisting of a polyacene derivative expressed by the following general
formula (3), each of R1, R2, R3, R4, R5 and
R6 in the general formula (3) satisfying the following
(condition-C1) and (condition-C):

##STR00005##

(Condition-C1)

[0030]R1, R2, R3, R4, R5 and R6 may be
independently the same substituents or different substituents but all of
R1, R4, R5 and R6 may never be hydrogen atoms at the
same time.

(Condition-C2)

[0031]Each of R1, R2, R3, R4, R5 and R6 is
at least one kind of substituent selected from a substituent family
consisting of an aliphatic hydrocarbon group which has substituents or no
substituents and of which number of carbon atoms ranges from 1 to 20, an
aromatic hydrocarbon group which has substituents or no substituents, a
complex aromatic group which has substituents or no substituents, a
carboxyl group, a hydride, an ester group, a cyano group, a hydroxyl
group, a thiocarboxyl group, a dithiocarboxyl group, a sulfonic acid
group, a sulfinic acid group, a sulfenic acid group, a sulfonyl group, a
sulfinyl group, an acyl halide group, a carbamoyl group, a hydrazide
group, an imide group, an amide group, an amidino group, an isocyano
group, a cyanic acid ester group, an isocyanic acid ester group, a
thiocyanic acid ester group, an isothiocyanic acid ester group, a formyl
group, a thioformyl group, an acyl group, a thiol group, an amino group,
an imino group, a hydrazino group, an alkoxy group, an arlyoxy group, an
ether group, a sulfide group, a disulfide group, a silyl group, a germyl
group, a stannyl group, a phosphino group, a boryl group, a halogen atom
and a hydrogen atom.

[0032]In the organic semiconductor material according to the third
embodiment, it is preferable that each of R1, R2, R3,
R4, R5 and R6 should be at least one kind of a substituent
selected from a substituent family consisting of an aliphatic hydrocarbon
group having a substituent and of which number of carbon atoms ranges
from 1 to 20, an aromatic hydrocarbon group having a substituent, a
complex aromatic group having a substituent, a carboxyl group, a hydride,
an ester group, a cyano group, a hydroxyl group, a halogen atom and a
hydrogen atom. For convenience sake of explanation, the above-mentioned
aspect will hereinafter be referred to as an "organic semiconductor
material according to the aspect 3A of the present invention".

[0033]In the organic semiconductor materials according to the third
embodiment or the aspect 3A, when a substituent is an aliphatic
hydrocarbon group, an alkyl group, an alkenyl group and an alkynyl group
can be enumerated as s substituents specifically.

[0034]Also, in the (condition-C2) in the organic semiconductor materials
according to the third embodiment or the aspect 3A, R1 to R6
are at least one kind of substituent selected from the substituent family
and this substituent may include a substituent containing more than one
kind of substituents properly selected from the substituent family.

[0035]In the organic semiconductor material according to the third
embodiment, Rm and Rm' (m and m' are integers ranging of from 1
to 6 and m≠m') may be cross-linked with each other to form a
saturated ring or an unsaturated ring (a structure including a double
bond or a tripe bond) of which number of carbon atoms lies in a range of
from 4 to 20. Also, in the organic semiconductor material according to
the aspect 3A, when R1 to R6 are the aliphatic hydrocarbon
group, a carboxyl group, a hydride, an ester group, a cyano group, a
hydroxyl group and a halogen atom may be bonded to a terminal of or
somewhere of this aliphatic hydrocarbon group in the branched state.
R2 and R3 may be crosslinked to form a saturated ring or
unsaturated ring of which number of carbon atoms lies in a range of from
4 to 20.

[0036]The (condition-C2) in the organic semiconductor material according
to the third embodiment is the condition identical to the (condition-A2)
in the organic semiconductor material according to the first aspect of
the present invention. In the (condition-C2), each of R1 to R6
is at least one kind of a substituent selected from a substituent family
consisting of 45 kinds in total. Accordingly, theoretically, 456
combinations exist at maximum as combinations of (R1, R2,
R3, R4, R5, R6), and any combinations may be used so
long as it can satisfy the (condition-C1). Also, the substituent family
in the organic semiconductor material according to aspect 3A is identical
to that in the organic semiconductor material according to aspect 1A.
Then, each of R1 to R6 is at least one kind of a substituent
selected from a substituent family consisting of 10 kinds of substituents
in total. Accordingly, in the organic semiconductor material according to
aspect 3A, 1010 combinations exist at maximum as the combinations of
(R1, R2, R3, R4, R5, R6) theoretically, and
any combination may be used so long as it can satisfy the (condition-C1).

[0037]In the organic semiconductor material according to the third
embodiment or aspect 3A, it is preferable that a substituent at a part of
an acene bone should be an alkyl group of which number of carbon atoms is
greater than 3 from a standpoint of improving its solubility relative to
an organic solvent more. The substituent at a part of the acene bond may
be, specifically, any one of substituents within R1 to R6.
Also, the cases in which all of R1 to R6 are the alkyl group of
which number of carbon atoms is greater than 3 may be included.

[0038]The organic semiconductor thin film according to the first
embodiment to attain the above-described objects is characterized in that
it is composed of the organic semiconductor materials according to the
first embodiment or aspect 1A including the above-mentioned various
preferred embodiments and that it has crystallinity.

[0039]Also, the organic semiconductor device according to the first
embodiment to attain the above-described objects is characterized in that
it includes the organic semiconductor thin film composed of the organic
semiconductor materials according to the first embodiment or aspect 1A
including the above-mentioned various preferred embodiments and that the
organic semiconductor thin film has crystallinity.

[0040]The organic semiconductor thin film according to the second
embodiment to attain the above-described objects is characterized in that
it is composed of the organic semiconductor materials according to the
second aspect or the aspect 2A of the present invention including the
above-mentioned various preferred embodiments and that it has
crystallinity.

[0041]Also, the organic semiconductor device according to the second
embodiment to attain the above-described objects is characterized in that
it includes the organic semiconductor thin film composed of the organic
semiconductor materials according to the second embodiment or aspect 2A
including the above-mentioned various preferred embodiments and that the
semiconductor thin film has crystallinity.

[0042]The organic semiconductor thin film according to the third
embodiment to attain the above-described objects is composed of the
organic semiconductor materials according to the third embodiment or
aspect 3A including the above-mentioned various preferred embodiments and
that it has crystallinity.

[0043]Also, an organic semiconductor device according to the third
embodiment to attain the above-described objects includes the organic
semiconductor thin film composed of the organic semiconductor materials
according to the third embodiment or the aspect 3A including the
above-mentioned various preferred embodiments and that the organic
semiconductor thin film has crystallinity.

[0044]The fact that "organic semiconductor thin film has crystallinity"
means that a solid substance having a spatial periodic atom sequence can
take a space lattice structure.

[0045]It is desirable that an organic semiconductor thin film should have
a stack structure although the present application is not limited
thereto. It is known that a pentacene without substituent takes a
herringbone structure (see FIG. 7). As compared with this herringbone
structure, a stack structure in which benzene rings are stacked in a
π-π fashion [crystal structure in which adjacent molecule planes
are stacked with each other (adjacent molecule planes have parallel
overlapping portions) and refer to FIG. 8] can realize an interaction of
a stronger conjugated plane and it has a possibility that it will improve
electric characteristics considerably. In the organic semiconductor
materials according to aspect 1A, aspect 2A or aspect 3A or the organic
semiconductor materials according to the first embodiment, the second
embodiment or the third embodiment including the preferred embodiments
(hereinafter, these organic semiconductor materials will be generally
referred to an "inventive organic semiconductor material"), in the
organic semiconductor thin films made of the inventive organic
semiconductor material and which are made according to the first
embodiment, the second embodiment or the third embodiment including the
above-mentioned preferred embodiments (hereinafter, these organic
semiconductor thin films will be generally referred to as an "inventive
organic semiconductor thin film") and in the organic semiconductor
devices including the organic semiconductor thin film made of the organic
semiconductor material of the present invention and according to the
first embodiment, the second embodiment and the third embodiment
including the above-mentioned preferred embodiments (hereinafter, these
organic semiconductor devices will be generally referred to as an
"inventive organic semiconductor device" and further, the inventive
organic semiconductor material, the inventive organic semiconductor thin
film and the inventive organic semiconductor device will be simply
referred to as the "present invention"), if the organic semiconductor
material is constructed by the polyacene derivative into which the
substituent is introduced and if the length of the introduced substituent
is controlled, then the polyacene can take the herringbone structure and
the stack structure. Further, according to the examination done by the
inventors of the present application, it became clear from the X-ray
crystal structure analysis that, as shown in FIGS. 4 to 6, the organic
semiconductor material can take the stack structure rather than the
herringbone structure as the length of the substituent is increased.
Further, it became clear that, when a substituent is an alkyl group, if a
substituent has a length up to the ethyl group (see FIG. 4), then the
organic semiconductor material can take the herringbone structure. Also,
it became clear that if a substituent has a length longer than a propyl
group (refer to FIG. 5 when a substituent is a propyl group and refer to
FIG. 6 when a substituent is a butyl group), then the organic
semiconductor material can take the stack structure.

[0046]An organic semiconductor device according to an embodiment is
composed of a source/drain electrode, a channel forming region sandwiched
between the source/drain electrode and the source/drain electrode, a gate
insulating layer and a gate electrode opposed to the channel forming
region through the gate insulating layer, and the channel forming region
can be constructed by the organic semiconductor thin film, that is, the
organic semiconductor device according to the present invention can be
constructed as an organic field-effect transistor (organic FET).

[0047]As specific structures of the organic field-effect transistor, the
following fours kinds of structures can be shown by way of example.

[0048]That is, an organic field-effect transistor having a first structure
is a so-called bottom gate/bottom contact type organic field-effect
transistor which includes (A) a gate electrode formed on a substrate, (B)
a gate insulating layer formed on the gate electrode and the substrate,
(C) a source/drain electrode formed on the gate insulating layer and (D)
a channel forming region composed of the organic semiconductor thin film
according to the present invention formed on the gate insulating layer
between the source/drain electrode and the source/drain electrode.

[0049]An organic field-effect transistor having a second structure is a
so-called bottom gate/top contact type organic field-effect transistor
which includes (A) a gate electrode formed on a substrate, (B) a gate
insulating layer formed on the gate electrode and the substrate, (C) a
channel forming region formed on the gate insulating layer and which is
made of the organic semiconductor thin film according to the present
invention and (D) a source/drain electrode formed on the organic
semiconductor thin film.

[0050]Further, an organic field-effect transistor having a third structure
is a so-called top gate/top contact type organic field-effect transistor
which includes (A) a channel forming region formed on a substrate and
which is formed on an organic semiconductor thin film according to the
present invention, (B) a source/drain electrode formed on the organic
semiconductor thin film, (C) a gate insulating layer formed on the
source/drain electrode and the organic semiconductor thin film and (D) a
gate electrode formed on the gate insulating layer.

[0051]Also, an organic field-effect transistor having a fourth structure
is a so-called top gate/bottom contact type organic field-effect
transistor which includes (A) a source/drain electrode formed on a
substrate, (B) a channel forming region formed on the source/drain
electrode and the substrate and which is formed of the organic
semiconductor thin film according to the present invention, (C) a gate
insulating layer formed on the organic semiconductor thin film and (D) a
gate electrode formed on the gate insulating layer.

[0053]As methods of forming a gate insulating layer, there can be
enumerated any one of various kinds of printing methods such as a screen
printing method, an ink-jet printing method, an offset printing method
and a gravure printing method; various kinds of coating methods such as
an air doctor coating method, a blade coating method, a rod coating
method, a knife coating method, a squeeze coating method, a reverse roll
coating method, a transfer roll coating method, a gravure coating method,
a kis coating method, a cast coating method, a spray coating method, a
slit orifice coating method, a calender coating method and a die coating
method; a dipping method; a casting method; a spin coating method; a
spray method; various kinds of CVD (chemical vapor deposition) methods;
and various kinds of PVD (physical vapor deposition) methods. As the PVD
methods, there can be enumerated various kinds of ion plating methods
such as (a) various kinds of vacuum deposition methods such as an
electron beam heating method, a resistance heating method and a flash
vapor deposition method, (b) a plasma deposition method, (c) various
kinds of sputtering methods such as a bipolar sputtering method, a DC
sputtering method, a DC magnetron sputtering method, a high-frequency
sputtering method, a magnetron sputtering method, an ion beam sputtering
method and a bias sputtering method and (d) various kinds of ion plating
methods such as a DC (direct current) method, an RF method, a
multi-cathode method, an activating reaction method, a field deposition
method, a high-frequency ion plating method and a reactive ion plating
method.

[0054]Alternatively, the gate insulating layer can be formed by oxidizing
or nitriding the surface of the gate electrode or the gate insulating
layer can be obtained by forming an oxide film or a nitride film on the
surface of the gate electrode. As a method of oxidizing the surface of
the gate electrode, there can be enumerated a thermal oxidation method,
an oxidation method using N2 plasma and an anode oxidation method
depending on materials constructing the gate electrode. As a method of
nitriding the surface of the gate electrode, there can be enumerated a
nitriding method using N2 plasma depending on the materials
constructing the gate electrode. Alternatively, when the gate electrode
is made of gold (Au), it is possible to form the gate insulating layer on
the surface of the gate electrode by coating the surface of the gate
electrode in a self-organization fashion with a suitable method such as a
dipping method based on insulating molecule having functional groups
capable of chemically forming bonds with the gate electrode like a
straight hydrocarbon of which one end is modified by a mercapto group.

[0056]As methods of forming the source/drain electrode, the gate electrode
and various kinds of wirings, depending on materials constructing the
source/drain electrode, the gate electrode and various kinds of wirings,
there can be used any one of a spin coating method; the above-mentioned
various kinds of printing methods using various conducting pastes and
various conducting polymer solutions; the above-mentioned various kinds
of coating methods; a lift-off method; a shadow mask method; an
electrolytic plating method, a nonelectrolytic plating or a plating
method of a combination of the electrolytic plating and the
nonelectrolytic plating; a spray method; the above-mentioned various
kinds of PVD methods; and various kinds of CVD methods including an MOCVD
(metal organic chemical vapor deposition) method or combinations of the
above-mentioned methods and patterning technologies if necessary.

[0057]As the substrate, there can be enumerated various kinds of glass
substrates, various kinds of glass substrates with insulating films
formed on their surfaces, a quartz substrate, a quartz substrate with an
insulating film formed on its surface and a silicon substrate with an
insulating film formed on its surface. Further, as the substrate, there
can be enumerated plastic films and plastic sheet plastic substrates
consisting of polymer materials such as polyethersulfone (PES),
polyimide, polycarbonate (PC), poly (ethylene terephthalate) (PET), poly
(methyl methacrylate) (PMMA), poly (vinyl alcohol) (PVA), poly (vinyl
phenol) (PVP). If a substrate consisting of polymer materials with
flexibility is used, then an organic semiconductor device can be
assembled into or unitarily formed with display apparatus and electronic
devices having curved-surface shapes. In addition, conducting substrates
(substrates made of metals such as gold and graphite with high
orientation) can be enumerated as the substrate. Also, it is frequently
observed that an organic semiconductor device is provided on a supporting
member depending on the arrangement and structure of the organic
semiconductor device. The supporting member in such a case also can be
constructed by the above-mentioned materials.

[0058]When the organic semiconductor device is applied to and used with
display apparatus and various kinds of electronic devices, the organic
semiconductor device can be formed as a monolithic integrated circuit in
which a large number of organic semiconductor devices are integrated on
the substrate. Each organic semiconductor device can be cut and
separately used as discrete assemblies. Also, the organic semiconductor
device can be shielded by a resin.

[0059]According to an embodiment, since the organic semiconductor material
is constructed by the polyacene derivative into which the substituent is
introduced, affinity of the organic semiconductor material relative to an
organic solvent can be improved and it becomes possible to dissolve the
organic semiconductor material into a wide variety of organic solvents at
room temperature. Thus, at room temperature, organic semiconductor
materials of quantities required by coating processes such as a spin
coating method; a dipping (dip coating) method; various kinds of coating
methods such as an air doctor coating method, a blade coating method, a
rod coating method, a knife coating method, a squeeze coating method, a
reverse roll coating method, a transfer roll coating method, a gravure
coating method, a kis coating method, a cast coating method, a spray
coating method, a slit orifice coating method, a calender coating method
and a die coating method; various kinds of printing methods such as a
screen printing method, an ink-jet printing method, an offset printing
method and a gravure printing method; a casting method; and a spray
method can be dissolved into a wide variety of organic solvents such as
hydrocarbon-based solvents (for example, hexane, heptane, octane,
cyclohexane), ester-based solvents (for example, ethyl acetate,
butyllactone), alcohol-based solvents (for example, octanol, hexanol,
benzyl alcohol), aromatic-based solvents (for example, toluene,
mesitylene, benzene), ether-based solvents (for example, diethyl ether,
tetrahydrofuran), halogen-based solvents (for example, chloroform,
dichloromethane) and ketone-based solvents (for example, acetone,
cyclopentanone).

[0060]A polyacene compound is a compound in which benzene rings are bonded
in a straight fashion and a polyacene compound without substituent has
properties in which it becomes more difficult to be dissolved into an
organic solvent in accordance with the increase of the number of benzene
rings. In particular, a polyacene greater than pentacene having five
benzene rings bonded loses solubility relative to almost all of organic
solvents and it is difficult to form a uniform film based on a suitable
method such as a spin coating method. If possible, then it is unavoidable
that the organic solvent available in this case is limited to extremely
limited organic solvents and temperature conditions. However, according
to an embodiment, since the organic semiconductor material consists of
the polyacene derivatives into which the substituents were introduced, it
is possible to improve solubility of the organic semiconductor material
relative to various kinds of organic solvents. Hence, it is possible to
form/deposit a uniform film based on the coating process such as the spin
coating method. As earlier noted, since 2,3,9,10-tetramethyl pentacene
and 2,3-dimethyl pentacene are known well, it has been reported that, if
1,2-dichlorobenzene with high extractability is used, then the organic
semiconductor material is slightly dissolved in the state in which it is
warmed. Therefore, it can be gathered from this report that introduction
of substituents into the polyacene derivatives in the organic
semiconductor material considerably affects solubility of the organic
semiconductor materials into the organic solvents.

[0061]Also, according to an embodiment, not only the solubility of the
organic semiconductor material with respect to the organic solvent can be
improved but also oxidation resistance can be improved and control of
packing rules (herringbone structure/stack structure) in the organic
semiconductor thin film and crystallinity can be improved by the
introduction of substituents. Further, by using the polyacene derivative
in which a substituent with a polarity and a substituent without polarity
are introduced into desired positions, it becomes possible to control
orientation and inclination of the organic semiconductor material
relative to a base material (underlying layer or substrate). Also, it
becomes possible to carry out patterning on the organic semiconductor
material by bonding the polyacene derivative to functional groups
introduced into desired positions of a base material (underlying layer or
substrate). Further, the polyacene derivatives have a possibility that
they will change their conductivity types depending on the substituents.
It is known that, while ordinary pentacene without substituent behaves as
a p-type semiconductor, pentacene in which all hydrogen atoms are
replaced with fluorine atoms acts as an n-type semiconductor. Then,
according to the present invention, since the organic semiconductor
material is formed as the polyacene derivative into which the
substituents are introduced, electron transition energy is changed with
the result that it becomes possible to control a conductivity type.

[0062]Additional features and advantages are described herein, and will be
apparent from, the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

[0063]FIG. 1A is a schematic cross-sectional view showing a part of an
organic field-effect transistor which is which might be called a bottom
gate/top contact type organic field-effect transistor;

[0064]FIG. 1B is a schematic cross-sectional view showing a part of an
organic field-effect transistor which is what might be called a bottom
gate/bottom contact type organic field-effect transistor;

[0065]FIG. 2A is a schematic cross-sectional view showing a part of an
organic field-effect transistor which is what might be called a top
gate/top contact type organic field-effect transistor;

[0066]FIG. 2B is a schematic cross-sectional view showing a part of an
organic field-effect transistor which is what might be called a top
gate/bottom contact type organic field-effect transistor;

[0067]FIG. 3 is a schematic cross-sectional view showing a part of organic
field-effect transistor test products according to respective inventive
examples;

[0068]FIG. 4 is a diagram showing an X-ray crystalline structure analysis
of an organic semiconductor material in the form of a photograph in which
a substituent is an ethyl group;

[0069]FIG. 5 is a diagram showing an X-ray crystalline structure analysis
of an organic semiconductor material in the form of a photograph in which
a substituent is a propyl group;

[0070]FIG. 6 is a diagram showing an X-ray crystalline structure analysis
of an organic semiconductor material in the form of a photograph in which
a substituent is a butyl group;

[0071]FIG. 7 is a diagram showing a herringbone structure which is a
laminating structure of a molecule in an organic compound crystal; and

[0072]FIG. 8 is a diagram showing a stack structure of a laminating
structure of a molecule in an organic compound crystal.

DETAILED DESCRIPTION

[0073]Embodiments of the present invention will be described below in
detail with reference to the drawings.

Example 1

[0074]Example 1 relates to an organic semiconductor material, an organic
semiconductor thin film and an organic semiconductor device according to
a first or second mode of the present invention. A chemical formula of
the organic semiconductor material according to the inventive example 1
is shown as follows.

##STR00006##

[0075]The organic semiconductor material of the inventive example 1 is
made of a polyacene derivative shown by the following general formula
(1). In the general formula (1), R1, R2, R3, R4,
R5, R6, R7, R8, R9 and R10 are respectively
substituents which will follow. That is, the organic semiconductor
material of the inventive example 1 is 2,3-bis
methoxycarbonyl-1,4,6,13-tetrabutyl-8,9,10,11-tetraethyl pentacene.

##STR00007##

[0076]R1: aliphatic hydrocarbon group (concretely, butyl group)

[0077]R2: carbonyl group (concretely, methoxycarbonyl group)

[0078]R3: carbonyl group (concretely, methoxycarbonyl group)

[0079]R4: aliphatic hydrocarbon group (concretely, butyl group)

[0080]R5: aliphatic hydrocarbon group (concretely, butyl group)

[0081]R6: aliphatic hydrocarbon group (concretely, ethyl group)

[0082]R7: aliphatic hydrocarbon group (concretely, ethyl group)

[0083]R8: aliphatic hydrocarbon group (concretely, ethyl group)

[0084]R9: aliphatic hydrocarbon group (concretely, ethyl group)

[0085]R10: aliphatic hydrocarbon group (concretely, butyl group)

[0086]Alternatively, the organic semiconductor material according to
example 1 is made of a polyacene derivative shown by the following
general formula (2). R1, R2, R3, R4, R5,
R6, R7 and R8 in the general formula (2) are the following
substituents, respectively. In the inventive example 1, an equality of
n=4 is satisfied. Also, R5 is expressed as R51, R52,
R53, R54 in the clockwise direction of the general formula, and
R8 is expressed as R81, R82, R83, R84 in the
clockwise direction of the general formula. This relationship will apply
for the following examples as well.

[0100]The organic semiconductor thin film according to example 1 is made
of the above-described organic semiconductor material and has
crystallinity. Also, the organic semiconductor device according to
example 1 is made of the above-described organic semiconductor material
and includes the organic semiconductor thin film having the
crystallinity.

[0101]Specifically, an organic field-effect transistor according to
example 1 is composed of a source/drain electrode 15, a channel forming
region 14 sandwiched by the source/drain region 15 and the source/drain
region 15, a gate insulating layer 13 and a gate electrode 12 opposed to
the channel forming region 14 through the gate insulating layer 13. More
specifically, as FIG. 1A shows a schematic fragmentary cross-sectional
view, an organic field-effect transistor of a so-called bottom gate/top
contact type according to example 1 is composed of (a) a gate electrode
12 formed on substrates 10 and 11 and which is formed of a metal film,
(b) a gate insulating layer 13 formed on the gate electrode 12 and the
substrates 10 and 11 and which is made of SiO2, (c) a channel
forming region 14 and a channel forming region extended portion 14A
formed on the gate insulating layer 13 and which are formed of the
organic semiconductor thin film of example 1 and (d) a source/drain
electrode 15 formed on the channel forming region extended portion 14A
and which is formed of a metal film. The substrates 10 and 11 are formed
of the substrate 10 made of a glass substrate and a SiO2 insulating
film 11 formed on the surface of the substrate 10. To be more concrete,
the gate electrode 12 and the gate insulating layer 13 are formed on the
insulating film 11.

[0102]An outline of a method of manufacturing a so-called bottom gate/top
contact type organic field-effect transistor (specifically, TFT
(thin-film transistor) using the organic semiconductor material according
to example 1 will be described below.

[PROCESS-100]

[0103]First, the gate electrode 12 is formed on the substrate (glass
substrate 10 and on which surface there is formed the SiO2
insulating film 11). Specifically, a resist layer (not shown) in which a
portion on which the gate electrode 12 should be formed is removed is
formed on the insulating film 11 by a lithography technique. After that,
a chromium (Cr) layer (not shown) that serves as a close-contact layer
and a gold (Au) layer that servers as the gate electrode 12 are
sequentially deposited on the whole surface by a vacuum evaporation
coating process and then the resist layer is removed. In this manner, the
gate electrode 12 can be obtained by a so-called lift off method.

[PROCESS-110]

[0104]Next, the gate insulating film 13 is formed on the substrate
(insulating film 11) which includes the gate electrode 12. Specifically,
the gate insulating film 13 made of SiO2 is deposited on the gate
electrode 12 and the insulating film 11 based on a sputtering method.
When the gate insulating film 13 is deposited on the gate electrode 12
and the insulating film 11, if a part of the gate electrode 12 is covered
with a hard mask, then it is possible to form a lead-out portion (not
shown) of the gate electrode 12 without photolithography process.

[PROCESS-120]

[0105]Next, the channel forming region 14 and the channel forming region
extended portion 14A are formed on the gate insulating layer 13.
Specifically, a solution in which 5 g of the organic semiconductor
material of the inventive example 1 that has been described before was
dissolved into 1 liter of a chloroform solution is coated on the gate
insulating film 13 at room temperature by a coating process such as a
spin coating method. Subsequently, when the above coated solution is
dried by a heating treatment at 60° C., the channel forming region
14 and the channel forming region extended portion 14A can be formed on
the gate insulating layer 13. According to the results of various
experiments, it is to be understood that organic field-effect transistors
obtained under the condition in which a temperature in which the coated
solution is to be dried lies in a range of from 60°
C.±5° C. exhibited best transistor characteristics.

[PROCESS-130]

[0106]After that, the source/drain electrodes 15 are formed on the channel
forming region extended portion 14A so as to sandwich the channel forming
region 14 there between. Specifically, a chromium (Cr) layer (not shown)
that serves as the close-contact layer and a gold (Au) layer that serves
as the source/drain electrode 15 are sequentially deposited on the whole
surface on the basis of the vacuum evaporation coating process. In this
manner, the structure shown in FIG. 1A can be obtained. When the gate
insulating film 13 is deposited on the gate electrode 12 and the
insulating film 11, if a part of the channel forming region extended
portion 14A is covered with a hard mask, then it is possible to form the
source/drain electrode 15 without photolithography process.

[PROCESS-140]

[0107]Last, after an insulating layer (not shown) that serves as a
passivation film was formed on the whole surface, an opening portion was
formed on the insulating layer above the source/drain electrode 15 and an
interconnection material layer was formed on the whole surface including
the inside of the opening portion, by treating the interconnection
material layer via a patterning process, it is possible to obtain a
bottom gate/top contact type organic field-effect transistor in which an
interconnection (not shown) connected to the source/drain electrode 15 is
formed on the insulating layer.

[0108]The organic field-effect transistor is not limited to the so-called
bottom gate/top contact type organic field-effect transistor and it can
be applied to various kinds of other organic field-effect transistors,
such as a so-called bottom gate/bottom contact type organic field-effect
transistor, a so-called top gate/top contact type organic field-effect
transistor and a so-called top gate/bottom contact type organic
field-effect transistor.

[0109]FIG. 1B is a schematically cross-sectional view showing a part of a
so-called bottom gate/bottom contact type organic field-effect
transistor. In FIG. 1B, elements and parts identical to those of FIG. 1A
are denoted by identical reference numerals. As shown in FIG. 1B, this
bottom gate/bottom contact type organic field-effect transistor includes
(a) the gate electrode 12 formed on the substrates 10 and 11, (b) the
gate insulating layer 13 formed on the gate electrode 12 and the
substrates 10 and 11, (c) the source/drain electrode 15 formed on the
gate insulating layer 13 and (d) the channel forming region 14 formed on
the gate insulating layer 13 at its portion sandwiched between the
source/drain electrodes 15 and 15.

[0110]An outline of a method for manufacturing a bottom gate/bottom
contact type TFT will be described below.

[PROCESS-200]

[0111]First, after the gate electrode 12 was formed on the substrate
(insulating film 11) similarly to the [process-100], the gate insulating
layer 13 is formed on the gate electrode 12 and the insulating film 11
similarly to the [process-110].

[PROCESS-210]

[0112]Next, the source/drain electrode 15 formed of a gold (Au) layer is
formed on the gate insulating layer 13. Specifically, the resist layer in
which a portion on which the source/drain electrode 15 should be formed
is removed is formed on the gate insulating layer 13 by the lithography
technique. Then, similarly to the [process-100], the chromium (Cr) layer
(not shown) that serves as the close-contact layer and the gold (Au)
layer that serves as the source/drain electrode 15 are sequentially
deposited on the resist layer and the gate insulating layer 13 by the
vacuum evaporation coating process and then the resist layer is removed.
In this manner, the source/drain electrode 15 can be obtained based on
the so-called lift off method.

[PROCESS-220]

[0113]After that, based on a method similar to that of the [process-120],
the channel forming region 14 is formed on the gate insulating layer 13
at its portion sandwiched between the source/drain electrodes 15 and 15.
In this manner, it is possible to obtain the structure shown in FIG. 1B.

[PROCESS-230]

[0114]Finally, it is possible to obtain the bottom gate/bottom contact
type organic field-effect transistor by executing a process similar to
that of the [process-140].

[0115]FIG. 2A is a schematic cross-sectional view showing a part of a
so-called top gate/top contact type organic field-effect transistor. In
FIG. 2A, elements and parts identical to those of FIG. 1A are denoted by
identical reference numerals.

[0116]As shown in FIG. 2A, this top gate/top contact type organic
field-effect transistor includes (a) the channel forming region 14 and
the channel forming region extended portion 14A formed on the substrates
10 and 11, (b) the source/drain electrode 15 formed on the channel
forming region extended portion 14A, (c) the gate insulating layers 13
formed on the source/drain electrode 15 and the channel forming region 14
(a) the channel forming region 14 and the channel forming region extended
portion 14A formed on the substrates 10 and 11, (b) the source/drain
electrode 15 formed on the channel forming region extended portion 14A,
(c) the gate insulating layers 13 formed on the source/drain electrode 15
and the channel forming region 14 and (d) the gate electrode 12 formed on
the gate insulating layer 13.

[0117]An outline of a method of manufacturing a top gate/top contact type
TFT will be described below.

[PROCESS-300]

[0118]First, the channel forming region 14 and the channel forming region
extended portion 14A are formed on the substrate (the glass substrate 10
and on which surface there is formed the insulating film 11 made of
SiO2) on the basis of a method similar to that of the [process-120].

[0119][PROCESS-310]

[0120]Next, the source/drain regions 15 and 15 are formed on the channel
forming region extended portion 14A so as to sandwich the channel forming
region 14 there between. Specifically, the chromium (Cr) layer (not
shown) that serves as the close-contact layer and the gold (Au) layer
that serves as the source/drain electrode 15 are deposited on the whole
surface, in that order, by the vacuum evaporation coating process. When
the source/drain electrodes 15 are deposited on the channel forming
region extended portion 14A, if a part of the channel forming region
extended portion 14A is covered with a hard mask, then it is possible to
form the source/drain electrodes 15 without photolithography process.

[PROCESS-320]

[0121]Next, the gate insulating layer 13 is formed on the source/drain
electrode 15 and the channel forming region 14. Specifically, it is
possible to form the gate insulating layer 13 on the source/drain
electrode 15 and the channel forming region 14 by depositing PVA (poly
(vinyl alcohol)) on the whole surface based on the spin coating method.

[PROCESS-330]

[0122]After that, the gate electrode 12 is formed on the gate insulating
layer 13. Specifically, the chromium (Cr) layer (not shown) that serves
as the close-contact layer and the gold (Au) layer that serves as the
gate electrode 12 are deposited on the whole surface, in that order, by
the vacuum evaporation coating process. In this manner, it is possible to
obtain the structure shown in FIG. 2A. When the gate electrode 12 is
deposited on the gate insulating layer 13, if a part of the gate
insulating layer 13 is covered with the hard mask, then it is possible to
form the gate electrode 12 without photolithography process. Last, it is
possible to obtain the top gate/top contact type organic field effect
transistor by executing a process similar to that of the [process-140].

[0123]FIG. 2B is a schematic cross-sectional view showing a part of the
so-called top gate/bottom contact type organic field-effect transistor.
In FIG. 2B, elements and parts identical to those of FIG. 2A are denoted
by identical reference numerals.

[0124]As shown in FIG. 2B, this top gate/bottom contact type organic
field-effect transistor includes (a) the source/drain electrodes 15
formed on the substrates 10 and 11, (b) the channel forming region 14
formed on the substrates 10 and 11 at their portions sandwiched by the
source/drain electrodes 15 and 15, (c) the gate insulating layer 13
formed on the channel forming region 14 and (d) the gate electrode 12
formed on the gate insulating layer 13.

[0125]An outline of a method of manufacturing a top gate/bottom contact
type TFT will be described below.

[PROCESS-400]

[0126]First, the source/drain electrode 15 is formed on the substrate (the
glass substrate 10 and on which surface there is formed the insulating
film 11 made of SiO2). Specifically, the chromium (Cr) layer (not
shown) that serves as the close-contact layer and the gold (Au) layer
that serves as the source/drain electrode 15 are deposited on the
insulating film 11 by the vacuum evaporation coating process. When the
source/drain electrode 15 is deposited on the insulating film 11, if a
part of the substrate (insulating film 11) is covered with the hard mask,
then it is possible to form the source/drain electrode 15 without
photolithography process.

[PROCESS-410]

[0127]After that, the channel forming region 14 is formed on the substrate
(the insulating film 11) at its portion sandwiched by the source/drain
electrodes 15 on the basis of a method similar to that of the
[process-120]. In actual practice, the channel forming region extended
portion 14A is formed on the source/drain electrode 15.

[PROCESS-420]

[0128]Next, the gate insulating layer 13 is formed on the source/drain
electrode 15 and the channel forming region 14 (in actual practice, the
gate insulating layer 13 is formed on the channel forming region 14 and
the channel forming region extended portion 14A) similarly to the
process-320].

[PROCESS-430]

[0129]After that, similarly to the process-330], the gate electrode 12 is
formed on the gate insulating layer 13. In this manner, it is possible to
obtain the structure shown in FIG. 2B. Last, it is possible to obtain the
top gate/bottom contact type organic field-effect transistor by executing
a process similar to that of the [process-140].

[0130]Also in the inventive examples 2 to 10 which will follow, the
organic field-effect transistor can be formed as any one of the bottom
gate/top contact type organic field-effect transistor, the bottom
gate/bottom contact type organic field-effect transistor, the top
gate/top contact type organic field-effect transistor and the top
gate/bottom contact type organic field-effect transistor and they can be
manufactured based on the above-mentioned methods.

[0131]Operations of a test product of an organic field-effect transistor
having a channel forming region, which was formed based on a coating
process such as a spin coating method using a chloroform solution
(concentration: 5 g/lit.) of the organic semiconductor material of the
inventive example 1 at room temperature, were checked. FIG. 3 is a
schematic cross-sectional view showing a part of the above test product
of the organic field-effect transistor. As a result, gate modulation
could be confirmed and hence it could be confirmed that the organic
semiconductor thin film played a role of the channel forming region.
Depending on the conditions of the spin coating and the like, mobility of
5.0×10-5 to 1.2×10-3 cm2V-1second-1
could be obtained as mobility in the saturation region at that time.

[0132]Further, the organic semiconductor materials of the inventive
example 1 were prepared at room temperature in which ethyl acetate,
acetone, toluene, tetrahydrofuran, tetrahydropyran, cyclopentane and
mesitylene were used as solvents instead of chloroform (concentration: 5
g/lit.). Then, organic field-effect transistor test products were
manufactured by using the above respective prepared solutions based on
the similar methods and operations of the thus manufactured organic
field-effect transistor test products were checked. As a result, organic
semiconductors could be formed and deposited even when any prepared
solution was used. Further, gate modulation could be confirmed and hence
it could be confirmed that the organic semiconductor thin film played a
role of the channel forming region.

[0133]A method of synthesizing polyacene derivatives constructing the
organic semiconductor materials of the inventive example 1 will be
described below. Until otherwise specified, operations concerning
synthesis were carried out under the atmosphere of an inert gas by using
deoxidized and dehydrated solvents. Also, with respect to a synthesis
scheme, refer to J. Am. Chem. Soc. 112, 12876-12877 (2000).

[OPERATION-10]

[0134]First, 8.8 g of Cp2ZrCl2 was dissolved into 100 ml of
tetrahydrofuran (THF) and cooled to -78° C. After that, 38 ml of
n-BuLi hexane solution (1.6 mol/lit) was added to the resultant solution
and stirred at -78° C. for one hour. After 6.9 ml of 3-hexyne was
added to the resultant solution and stirred at room temperature for three
hours, whereafter 6.0 g of copper (I) chloride and 1 ml of Dimethyl
acetylenedicarboxylate (hereinafter referred to as a "DMAD") was added to
the resultant solution and stirred at room temperature for three hours.
Subsequently, 3N hydrochloric acid was added to the resultant solution
and reaction was ended. The resultant product was extracted three times
by using 100 ml of hexane solution, sequentially rinsed with saturated
sodium hydrogencarbonate and saturated brine and then dried by using
magnesium sulfate. After that, a solvent is removed from the resultant
product and refined by column chromatography (developing solvent): ethyl
acetate/hexane=1/5) and thereby 5.6 g of the following compound (1. 1)
could be obtained as a solid material (isolated yield: 61%).

##STR00009##

[OPERATION-11]

[0135]Next, 1.0 g of LiAlH4 was added to 47 ml of THE cooled at
0° C. and 4.2 g of a compound (1. 1) was added to this solution at
0° C. Then, after the resultant solution was stirred at room
temperature for three hours, water was added to this resultant solution
and reaction was ended. Next, 2N sulfuric acid was added to the resultant
solution so that the resultant solution may become slightly acid. This
solution was extracted three times by using 50 ml of diethyl ether,
rinsed with saturated brine and then dried by using magnesium sulfate.
Then, after the solvent was dried by the evaporator, the resultant
solvent was recrystallized and thereby 3.0 g of a compound (1. 2) could
be obtained as a solid crystal (yield: 90%).

##STR00010##

[OPERATION-12]

[0136]After that, 3.0 g of a compound (1. 2) was dissolved into 45 ml of
chloroform to which 1.5 ml of PBr3 was added. Then, after the
solution was stirred at room temperature for three hours, water was added
to the resultant solution. Then, the resultant solution was extracted
three times by 50 ml of ethyl acetate, sequentially rinsed with saturated
sodium hydrogencarbonate and saturated brine and then dried by using
magnesium sulfate. Subsequently, the solvent was removed from the
resultant solution by using the evaporator and recrystallized by hexane
and thereby 4.5 g of a compound (1. 3) could be obtained as a white solid
(yield: 99%).

##STR00011##

[OPERATION-13]

[0137]Next, 4.0 ml of 1-hexyne was added to 100 ml of THF. In the state in
which a resultant solution was cooled at -78° C., 20 ml of n-BuLi
hexane solution (1.6 mol/lit.) was added to the resultant solution and
stirred at room temperature for one hour. After that, in the state in
which a reaction solution was cooled at -78° C., 3.7 ml of DMPU
and 3.0 g of dibromo material [compound (1. 3)] dissolved into THF were
added to the resultant solution and stirred at room temperature for three
hours. Next, 3N hydrochloric acid was added to the resultant solution and
then reaction was ended. Next, the resultant solution was extracted three
times by 100 ml of hexane, sequentially rinsed with saturated sodium
hydrogencarbonate and saturated brine and then dried by using magnesium
sulfate. Subsequently, the solvent was removed from the resultant
solution by using the evaporator and refined by the column chromatography
(developing solvent: ethyl acetate/hexane=1/10) and thereby 2.6 g of a
compound (1. 4) could be obtained (yield: 83%)

##STR00012##

[OPERATION-14]

[0138]After that, after 0.29 g of Cp2ZrCl2 was dissolved into
5.0 ml of THE and cooled at -78° C., 1.3 ml of n-BuLi hexane
solution (1.6 mol/lit.) was added to the resultant solution and the
resultant solution was stirred at -78° C. for one hour. Next, 0.38
g of compound (1. 4) in the state in which it was dissolved into the THE
was added to the resultant solution and stirred at room temperature for
three hours. Thereafter, 6.0 g of copper (I) chloride was added to the
resultant solution and the resultant solution was cooled at 0° C.
After that, 11 ml of DMAD was added to the resultant solution and stirred
at room temperature for three hours. Then, 3N hydrochloric acid was added
to the resultant solution and then reaction was ended. Next, the
resultant solution was extracted three times by 20 ml of hexane,
sequentially rinsed with saturated sodium hydrogencarbonate and saturated
brine and then dried by using magnesium sulfate. Subsequently, the
solvent was removed from the resultant solution by using the evaporator
and refined by the column chromatography (developing solvent: ethyl
acetate/hexane=1/10) and thereby 0.49 g of a compound (1. 5) could be
obtained as a solid material (isolated yield: 95%).

##STR00013##

[OPERATION-15]

[0139]Next, 5.0 g of a compound (1. 5) and 2.2 g of DDQ were dissolved
into 100 ml of toluene and refluxed for three hours. After that, the
filtered solution was distillated under reduced pressure. Then, the
resultant solid was refined by the column chromatography (developing
solvent: ethyl acetate/hexane=1/9) and 4.9 g of a compound (1. 6) could
be obtained as a solid material (yield: 99%).

##STR00014##

[OPERATION-16]

[0140]Next, 0.72 g of LiAlH4 was added to 150 ml of THE cooled at
0° C. and 4.9 g of a compound (1. 6) was added to this solution at
0° C. Then, after the resultant solution was stirred at room
temperature for three hours, water was added to this resultant solution
and reaction was ended. Then, 2N sulfuric acid was added to the resultant
solution so that the resultant solution may become slightly acid. This
solution was extracted three times by using 100 ml of diethyl ether,
rinsed with the saturated brine and then dried by using magnesium
sulfate. Then, after the solvent was distillated under reduced pressure
by the evaporator, 40 ml of chloroform was added to the resultant
solution into which 0.95 ml of PBr3 was added. Then, after the
resultant solution was stirred at room temperature for 12 hours, water
was added to the resultant solution and reaction was ended. Then, the
resultant solution was extracted three times by using 100 ml of ethyl
acetate, sequentially rinsed with saturated sodium hydrogencarbonate and
saturated brine and dried by using magnesium sulfate. Thereafter, after
the solvent was removed from the resultant solution by the evaporator,
the resultant solution was recrystallized by hexane and thereby 5.6 g of
a compound (1. 8) could be obtained as a white solid (yield: 99%).

##STR00015##

[OPERATION-17]

[0141]Next, 0.23 ml of 1-hexyne was added to 50 ml of THF. In the state in
which a resultant solution was cooled at -78° C., 1.3 ml of n-BuLi
hexane solution (1.6 mol/lit.) was added to the resultant solution and
stirred at room temperature for one hour. After that, in the state in
which a reaction solution was cooled at -78° C., 0.25 ml of DMPU
and 0.20 g of dibromo material [compound (1. 8)] dissolved into the THF
were added to the resultant solution and stirred at room temperature for
three hours. Next, 3N hydrochloric acid was added to the resultant
solution and then reaction was ended Next, the resultant solution was
extracted three times by 100 ml of hexane, sequentially rinsed with
saturated sodium hydrogencarbonate and saturated brine and then dried by
using magnesium sulfate. Subsequently, the solvent was removed from the
resultant solution by using the evaporator and refined by the column
chromatography (developing solvent: ethyl acetate/hexane=1/50) and
thereby 0.17 g of a compound (1. 9) could be obtained (yield: 85%).

##STR00016##

[OPERATION-18]

[0142]After that, after 0.085 g of Cp2ZrCl2 was dissolved into
5.0 ml of THF and cooled at -78° C., 0.37 ml of n-BuLi hexane
solution (1.6 mol/lit.) was added to the resultant solution and the
resultant solution was stirred at -78° C. for one hour. Next, 0.17
g of compound (1. 9) in the state in which it was dissolved into the THE
was added to the resultant solution and stirred at room temperature for
three hours. Thereafter, 0.058 g of copper (I) chloride was added to the
resultant solution and the resultant solution was cooled at 0° C.
After that, 0.11 ml of DMAD was added to the resultant solution and
stirred at room temperature for three hours. Then, 3N hydrochloric acid
was added to the resultant solution and then reaction was ended. Next,
the resultant solution was extracted three times by 20 ml of chloroform,
sequentially rinsed with saturated sodium hydrogencarbonate and saturated
brine and then dried by using magnesium sulfate. Subsequently, the
solvent was removed from the resultant solution by using the evaporator
and refined by the column chromatography (developing solvent: chloroform)
and thereby 0.12 g of a compound (1. 10) could be obtained as a solid
material (isolated yield: 57%).

##STR00017##

[OPERATION-19]

[0143]After that, in the inert gas atmosphere, 2.0 g of compound (1. 10)
and 0.68 g (equivalent weight is 1.1) of DDQ were dissolved into 100 ml
of toluene and refluxed for 24 hours. Next, after the toluene of the
solvent was decreased to 20 ml by distillation under reduced-pressure and
thereby the resultant solution was changed into a saturated solution, 500
ml of methanol was added to the resultant solution and thereby
precipitate was produced. Then, after the precipitate was filtered, the
resultant product was dried and thereby 1.1 g of the pentacene derivative
[compound (1. 11)] of the inventive example 1 could be obtained (yield:
54%).

##STR00018##

Example 2

[0144]Example 2 is a modified example of example 1. A chemical formula of
an organic semiconductor material of example 2 is shown as follows.

##STR00019##

[0145]The organic semiconductor material of example 2 is made of a
polyacene derivative shown by the above-described general formula (1). In
the general formula (1), R1r R2, R3r R4, R5,
R6, R-7, R8, R9 and R10 are respectively
substituents which will follow. That is, the organic semiconductor
material of example 2 is 2,3-bis methoxycarbonyl-1,4,6,8,9,10,11
13-octaethyl pentacene.

[0146]R1: aliphatic hydrocarbon group (concretely, ethyl group)

[0147]R2: carbonyl group (concretely, methoxycarbonyl group)

[0148]R3: carbonyl group (concretely, methoxycarbonyl group)

[0149]R4: aliphatic hydrocarbon group (concretely, ethyl group)

[0150]R5: aliphatic hydrocarbon group (concretely, ethyl group)

[0151]R6: aliphatic hydrocarbon group (concretely, ethyl group)

[0152]R7: aliphatic hydrocarbon group (concretely, ethyl group)

[0153]R8: aliphatic hydrocarbon group (concretely, ethyl group)

[0154]R9: aliphatic hydrocarbon group (concretely, ethyl group)

[0155]R10: aliphatic hydrocarbon group (concretely, ethyl group)

[0156]Alternatively, the organic semiconductor material according to
example 2 is made of a polyacene derivative shown by the above-described
general formula (2). R1, R2, R3, R4, R5,
R6, R7 and R8 in the general formula (2) are the following
substituents, respectively. Also in the inventive example 2, an equality
of n=4 is satisfied.

[0168]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using the chloroform solution (concentration: 5
g/lit.) of the organic semiconductor material of example 2 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 1.5×105
cm2V-1 second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

[0169]A method of synthesizing polyacene derivatives constructing the
organic semiconductor material of the inventive example 2 will be
described below.

[OPERATION-20]

[0170]First, [OPERATION-10] to [OPERATION-12] are executed.

[OPERATION-21]

[0171]Next, 7.5 g of 1-butyne was dissolved into 300 ml of THF. In the
state in which a resultant solution was cooled at -78° C., 88 ml
of n-BuLi hexane solution (1.6 mol/lit.) was added to the resultant
solution and stirred at room temperature for one hour. After that, in the
state in which a reaction solution was cooled at -78° C., 17 ml of
DMPU and 8.7 g of dibromo material [compound (1. 3)] dissolved into the
THF were added to the resultant solution and stirred at room temperature
for five hours. Next, 3N hydrochloric acid was added to the resultant
solution and then reaction was ended. Next, the resultant solution was
extracted three times by 100 ml of hexane, sequentially rinsed with
saturated sodium hydrogencarbonate and saturated brine and then dried by
using magnesium sulfate. Subsequently, the solvent was removed from the
resultant solution by using the evaporator and refined by a
recrystallization method and thereby 5.9 g of a compound (2. 4) could be
obtained (yield: 79%)

##STR00020##

[OPERATION-22]

[0172]After that, after 5.4 g of Cp2ZrCl2 was dissolved into 100
ml of THF and cooled at -78° C., 24 ml of n-BuLi hexane solution
(1.6 mol/lit.) was added to the resultant solution and the resultant
solution was stirred at -78° C. for one hour. Next, 5.9 g of
compound (2. 4) in the state in which it was dissolved into the THE was
added to the resultant solution and stirred at room temperature for three
hours. Thereafter, 3.6 g of copper (I) chloride was added to the
resultant solution and the resultant solution was cooled at 0° C.
After that, 7.6 ml of DMAD was added to the resultant solution and
stirred at room temperature for three hours. Then, 3N hydrochloric acid
was added to the resultant solution and then reaction was ended. Next,
the resultant solution was extracted three times by 200 ml of hexane,
sequentially rinsed with saturated sodium hydrogencarbonate and saturated
brine and then dried by using magnesium sulfate. Subsequently, the
solvent was removed from the resultant solution by using the evaporator
and refined by the column chromatography (developing solvent: ethyl
acetate/hexane=1/5) and thereby 8.3 g of a compound (2. 5) could be
obtained as a solid material (isolated yield: 95%)

##STR00021##

[OPERATION-23]

[0173]Next, 8.3 g of compound (2. 5) and 4.1 g of DDQ were dissolved into
100 ml of toluene and refluxed for two hours.

[0174]After that, the resultant solution was filtered and the filtered
solution was distillated under reduced-pressure by the evaporator. The
resultant solid was dissolved into 10 ml of chloroform and 500 ml of
methanol was added to the resultant solution and thereby a precipitate
was obtained. Then, the precipitate was filtered and collected by a
funnel (manufactured by KIRIYAMA GLASS WORKS CO., LTD., under the trade
name of "KIRIYAMA ROHTO"), dried under reduced-pressure and thereby 5.2 g
of compound (2. 6) could be obtained as a solid material (isolated yield:
620).

##STR00022##

[OPERATION-24]

[0175]Next, 0.85 g of LiAlH4 was added to 150 ml of THE cooled at
0° C. and 5.2 g of a compound (2. 6) was added to this solution at
0° C. Then, after the resultant solution was stirred at room
temperature for three hours, water was added to this resultant solution
and reaction was ended. Then, 2N sulfuric acid was added to the resultant
solution so that the resultant solution may become slightly acid. This
solution was extracted three times by using 150 ml of diethyl ether,
rinsed with the saturated brine and then dried by using magnesium
sulfate. Then, after the solvent was distillated under reduced pressure
by the evaporator, 80 ml of chloroform was added to the resultant
solution into which 1.3 ml of PBr3 was added. Then, after the
resultant solution was stirred at room temperature for 12 hours, water
was added to the resultant solution and reaction was ended. Then, the
resultant solution was extracted three times by using 100 ml of ethyl
acetate, sequentially rinsed with saturated sodium hydrogencarbonate and
saturated brine and dried by using magnesium sulfate. Thereafter, after
the solvent was removed from the resultant solution by the evaporator,
the resultant solution was recrystallized by hexane and thereby 5.1 g of
a compound (2. 8) could be obtained as a white solid (yield: 86%).

##STR00023##

[OPERATION-25]

[0176]Next, 36 ml of n-BuLi hexane solution (1.6 mol/lit.) was added to
100 ml of THF cooled at -78° C. into which 3.1 g of 1-butyne was
added. After 1-butyne was completely added to the resultant solution, the
reaction solution was returned to room temperature and stirred for one
hour. Thereafter, the reaction solution was cooled to -78° C. into
which 7.2 ml of DMPU was added. Then, a solution in which 5.1 g of
compound (2. 8) was dissolved into 40 ml of THF was added to the
resultant solution and the resultant solution was returned to room
temperature and stirred for six hours. Then, after the reaction was
ended, 50 ml of 3N hydrochloric acid was added to the resultant solution
and the reaction was ended. Then, the resultant solution was extracted by
250 ml of ethyl acetate, rinsed with saturated sodium hydrogencarbonate
and saturated brine and dried by using magnesium sulfate. Thereafter,
after the magnesium sulfate and the organic solvent were separated by
filtering and the organic solvent was distillated under reduced-pressure
by the evaporator. Then, after the resultant solid was dissolved into
chloroform to produce a saturated solution, methanol of a quantity 50
times as large as the chloroform was added to the saturated solution and
thereby a precipitate was produced. The resultant precipitate was
filtered, separated and dried at reduced-pressure and thereby 3.6 g of a
target compound (2. 9) could be obtained (yield: 78%).

##STR00024##

[OPERATION-26]

[0177]Subsequently, 2.0 g of Cp2ZrCl2 was dissolved into 100 ml
of THE and cooled to -78° C. After that, 8.9 ml of n-BuLi hexane
solution (1.6 mol/lit) was added to the resultant solution and stirred at
-78° C. for one hour. 3.3 g of compound (2. 9) was added to the
resultant solution in the state in which the above compound was dissolved
into 50 ml of THE and stirred for three hours. Thereafter, 1.4 g of
copper (I) chloride was added to the resultant solution and cooled at
0° C. Next, 2.7 ml of DMAD was added to the resultant solution and
stirred at room temperature for six hours. Then, 50 ml of 3N hydrochloric
acid was added to the resultant solution and the reaction was ended.
Then, the resultant solution was extracted three times by using 200 ml of
ethyl acetate, sequentially rinsed with saturated sodium
hydrogencarbonate and saturated brine and dried by using magnesium
sulfate. Thereafter, after the magnesium sulfate and the organic solvent
were separated by filtering and the organic solvent was distillated under
reduced-pressure by the evaporator. Then, after the resultant solid was
dissolved into chloroform to produce a saturated solution, methanol of a
quantity 50 times as large as the chloroform was added to the saturated
solution and thereby a precipitate was produced. The resultant
precipitate was filtered, separated and dried at reduced-pressure and
thereby 2.4 g of a compound (2. 10) could be obtained (yield: 35%).

##STR00025##

[OPERATION-27]

[0178]After that, 2.4 g of compound (2. 10) and 0.87 g of DDQ were
dissolved into 80 ml of toluene and refluxed for 24 hours. Then, toluene
of solvent was distillated under reduced-pressure. Then, the resultant
solid was dissolved into 5.0 ml of chloroform to which 150 ml of methanol
was added and thereby a precipitate of a pentacene derivative [compound
(2. 11)] could be obtained. Next, the resultant precipitate was
recollected by filtering, dried under reduced-pressure and thereby 1.3 g
of pentacene derivative [compound (2. 11)] could be obtained (yield:
55%).

##STR00026##

Example 3

[0179]Example 3 also is a modified example of example 1. A chemical
formula of an organic semiconductor material according to example 3 is
shown as follows.

##STR00027##

[0180]The organic semiconductor material of example 3 is made of a
polyacene derivative shown by the above-described general formula (1). In
the general formula (1), R1r R2, R3, R4, R5,
R6, R7, R8, R9 and R10 are respectively
substituents which will follow. That is, the organic semiconductor
material of the inventive example 3 is 2,3-bis
methoxycarbonyl-8,9,10,11-tetra ethyl-1,4,6,13-tetra propyl pentacene.

[0181]R1: aliphatic hydrocarbon group (concretely, propyl group)

[0182]R2: carbonyl group (concretely, methoxycarbonyl group)

[0183]R3: carbonyl group (concretely, methoxycarbonyl group)

[0184]R4: aliphatic hydrocarbon group (concretely, propyl group)

[0185]R5: aliphatic hydrocarbon group (concretely, propyl group)

[0186]R6: aliphatic hydrocarbon group (concretely, ethyl group)

[0187]R7: aliphatic hydrocarbon group (concretely, ethyl group)

[0188]R8: aliphatic hydrocarbon group (concretely, ethyl group)

[0189]R9: aliphatic hydrocarbon group (concretely, ethyl group)

[0190]R10: aliphatic hydrocarbon group (concretely, propyl group)

[0191]Alternatively, the organic semiconductor material according to
example 3 is made of a polyacene derivative shown by the above-described
general formula (2). R1r R2, R3, R4, R5,
R6, R7 and R8 in the general formula (2) are the following
substituents, respectively. Also in the inventive example 3, an equality
of n=4 is satisfied.

[0205]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using the chloroform solution (concentration: 5
g/lit.) of the organic semiconductor material of example 3 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 9.0×10-6
cm2 V-1second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

[0206]A method of synthesizing polyacene derivatives constructing the
organic semiconductor material of example 3 will be described below.

[OPERATION-30]

[0207]First, [OPERATION-10] to [OPERATION-12] in example 1 are executed.

[OPERATION-31]

[0208]First, 5.9 ml of 1-pentyne was added to 50 ml of THF and cooled at
-78° C. In this state, 38 ml of n-BuLi hexane solution (1.6
mol/lit.) was added to the resultant solution and stirred at room
temperature for one hour. Thereafter, in the state in which a reaction
solution was cooled at -78° C., 7.5 ml of DMPU and 3.8 g of a
dibromo material [compound (1. 3)] dissolved into the THF were added to
the reaction solution and stirred at room temperature for five hours.
Then, 3N hydrochloric acid was added to the resultant solution and the
reaction was ended. The resultant product was extracted three times by
using 100 ml of hexane solution, sequentially rinsed with saturated
sodium hydrogencarbonate and saturated brine and then dried by using
magnesium sulfate. After that, a solvent is removed from the resultant
product by the evaporator and refined by the column chromatography
(developing solvent): ethyl acetate/hexane 1/50) and thereby 3.1 g of the
compound (3. 4) could be obtained (yield: 88%).

##STR00028##

[OPERATION-32]

[0209]After that, 2.6 g of Cp2ZrCl2 was dissolved into 50 ml of
the THF and cooled to -78° C. After that, 11 ml of n-BuLi hexane
solution (1.6 mol/lit.) was added to the resultant solution and stirred
at -78° C. for one hour. 3.1 g of a compound (3. 4) was added to
the resultant solution in the state in which the above compound was
dissolved into the THF and stirred at room temperature for three hours.
Thereafter, 1.8 g of copper (I) chloride was added to the resultant
solution and cooled at 0° C. Then, 32 ml of the DMAD was added to
the resultant solution and stirred at room temperature for three hours.
After that, 3N hydrochloric acid was added to the resultant solution and
the reaction was ended. Then, the resultant solution was extracted three
times by using 100 ml of hexane, sequentially rinsed with saturated
sodium hydrogencarbonate and saturated brine and dried by using magnesium
sulfate. After that, a solvent is removed from the resultant product by
the evaporator and refined by the column chromatography (developing
solvent): ethyl acetate/hexane=1/9) and thereby 2.9 g of a compound (3.
5) could be obtained as a solid material (isolated yield: 68%)

##STR00029##

[OPERATION-33]

[0210]Next, 2.9 g of compound (. 5) and 1.6 g of DDQ were dissolved into
60 ml of toluene and refluxed for three hours. After that, the resultant
solution was filtered and the filtered solution was distillated under
reduced-pressure by the evaporator. The resultant solid was refined by
the column chromatography (developing solvent: ethyl acetate/hexane=1/9)
and thereby 2.6 g of compound (3. 6) could be obtained as a solid
material (isolated yield: 89%).

##STR00030##

[OPERATION-34]

[0211]Next, 0.41 g of LiAlH4 was added to 100 ml of THE cooled at
0° C. and 2.6 g of a compound (3. 6) was added to this solution at
0° C. Then, after the resultant solution was stirred at room
temperature for three hours, water was added to this resultant solution
and the reaction was ended. Then, 2N sulfuric acid was added to the
resultant solution so that the resultant solution may become slightly
acid. This solution was extracted three times by using 100 ml of diethyl
ether, rinsed with the saturated brine and then dried by using magnesium
sulfate. Then, after the solvent was distillated by the evaporator, 40 ml
of chloroform was added to the resultant solution into which 0.51 ml of
PBr3 was added. Then, after the resultant solution was stirred at
room temperature for 12 hours, water was added to the resultant solution
and the reaction was ended. Then, the resultant solution was extracted
three times by using 100 ml of ethyl acetate, sequentially rinsed with
saturated sodium hydrogencarbonate and saturated brine and dried by using
magnesium sulfate. Thereafter, after the solvent was removed from the
resultant solution by the evaporator, the resultant solution was
recrystallized by hexane and thereby 2.4 g of a compound (3. 8) could be
obtained as a white solid (yield: 81%).

##STR00031##

[OPERATION-35]

[0212]Next, 2.6 ml of 1-pentyne was added to 100 ml of THE and cooled at
-78° C. In this state, 17 ml of n-BuLi hexane solution (1.6
mol/lit.) was added to the resultant solution, the resultant solution was
returned to room temperature and stirred for one hour. Thereafter, the
reaction solution was cooled to -78° C. into which 3.3 ml of DMPU
was added. Then, a solution in which 2.4 g of a compound (3. 8) was
dissolved into the THE was added to the resultant solution and the
resultant solution was returned to room temperature and stirred for three
hours. Then, 3N hydrochloric acid was added to the resultant solution and
the reaction was ended. Then, the resultant solution was extracted by 150
ml of hexane, rinsed with saturated sodium hydrogencarbonate and
saturated brine and dried by using magnesium sulfate. Thereafter, the
solvent was removed from the resultant solution by the evaporator and the
organic solvent was distillated under reduced-pressure by the evaporator.
Then, after the resultant solid was dissolved into chloroform to produce
a saturated solution, methanol of a quantity 50 times as large as the
chloroform was added to the saturated solution and thereby a precipitate
was produced. The resultant precipitate was separated by filtering and
dried at reduced-pressure and thereby 2.3 g of a target compound (3. 9)
could be obtained (yield: 99%).

##STR00032##

[OPERATION-36]

[0213]Subsequently, 1.9 g of Cp2ZrCl2 was dissolved into 100 ml
of THF and cooled to -78° C. After that, 8.4 ml of n-BuLi hexane
solution (1.6 mol/lit.) was added to the resultant solution and stirred
at -78° C. for one hour. 3.5 g of compound (3. 9) was added to the
resultant solution in the state in which the above compound was dissolved
into 50 ml of THF and stirred at room temperature for three hours.
Thereafter, 1.3 g of copper (I) chloride was added to the resultant
solution and cooled at 0° C. Next, 2.4 ml of DMAD was added to the
resultant solution and stirred at room temperature for six hours. Then,
50 ml of 3N hydrochloric acid was added to the resultant solution and the
reaction was ended. Then, the resultant solution was extracted by using
200 ml of ethyl acetate, sequentially rinsed with saturated sodium
hydrogencarbonate and saturated brine and dried by using magnesium
sulfate. Thereafter, the magnesium sulfate and the organic solvent were
separated by filtering and the organic solvent was distillated under
reduced-pressure by the evaporator. Then, after the resultant solid was
dissolved into chloroform to produce a saturated solution, methanol of a
quantity 50 times as large as the chloroform was added to the saturated
solution and thereby a precipitate was produced. The resultant
precipitate was separated by filtering and dried at reduced-pressure and
thereby 3.74 g of a compound (3. 10) could be obtained (yield: 84%).

##STR00033##

[OPERATION-37]

[0214]After that, 0.60 g of compound (3. 10) and 0.22 g of DDQ (1.1
equivalent weight) were dissolved into 12 ml of toluene and refluxed for
24 hours. Then, toluene used as the solvent was decreased to 6.0 ml by
distillation under reduced-pressure. Then, 120 ml of methanol was added
to the resultant solution and thereby a precipitate was produced. After
that, the resultant precipitate was filtered and rinsed with methanol and
dried and thereby 0.21 g of a pentacene derivative (3. 11) could be
obtained (yield: 34%).

##STR00034##

[0215]The X-ray crystal structure analysis was effected on the polyacene
derivative of example 1, the polyacene derivative of example 2 and the
polyacene derivative of example 3. As a result, it became clear that the
crystal structure was changed from the herringbone structure to the stack
structure as the alkyl chains at the positions of 1, 4, 6 and 13 are
extended.

Example 4

[0216]Example 4 also is a modified example of example 1. A chemical
formula of an organic semiconductor material of example 4 is shown as
follows.

##STR00035##

[0217]The organic semiconductor material according to example 4 is made of
a polyacene derivative shown by the above-described general formula (1).
In the general formula (1), R1, R2, R3, R4, R5,
R6, R7, R6r R9 and R10 are respectively
substituents which will follow. That is, the organic semiconductor
material of the inventive example 4 is 2,3-bis
methoxycarbonyl-1,4,6,13-tetrabuyl pentacene.

[0218]R1: aliphatic hydrocarbon group (concretely, butyl group)

[0219]R2: carbonyl group (concretely, methoxycarbonyl group)

[0220]R3: carbonyl group (concretely, methoxycarbonyl group)

[0221]R4: aliphatic hydrocarbon group (concretely, butyl group)

[0222]R5: aliphatic hydrocarbon group (concretely, butyl group)

[0223]R6: hydrogen atom

[0224]R7: hydrogen atom

[0225]R8: R8: hydrogen atom

[0226]R9: R9: hydrogen atom

[0227]R10: aliphatic hydrocarbon group (concretely, butyl group)

[0228]Alternatively, the organic semiconductor material according to
example 4 is made of a polyacene derivative shown by the above-described
general formula (2). R1, R2, R3, R4, R5,
R6, R7 and R8 in the general formula (2) are the following
substituents, respectively. Also in example 4, an equality of n=4 is
satisfied.

[0229]R1: aliphatic hydrocarbon group (concretely, butyl group)

[0230]R2: carbonyl group (concretely, methoxycarbonyl group)

[0231]R3: carbonyl group (concretely, methoxycarbonyl group)

[0232]R4: aliphatic hydrocarbon group (concretely, butyl group)

[0233]R51: hydrogen atom

[0234]R52: aliphatic hydrocarbon group (concretely, butyl group)

[0235]R53: hydrogen atom

[0236]R54: hydrogen atom

[0237]R6: hydrogen atom

[0238]R7: hydrogen atom

[0239]R81: hydrogen atom

[0240]R82: hydrogen atom

[0241]R83: aliphatic hydrocarbon group (concretely, butyl group)

[0242]R84: hydrogen atom

[0243]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using the chloroform solution (concentration: 5
g/lit.) of the organic semiconductor material of example 4 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 9.0×10-5
cm2 V-1 second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

[0244]Also, experiments were carried out in which the polyacene derivative
of example 1, the polyacene derivative of example 2, the polyacene
derivative of example 3 and the polyacene derivative of example 4 were
respectively dissolved into hexane solution at room temperature. As a
result, while the polyacene derivative of example 2 in which 80% of the
substituents is the ethyl group was hardly dissolved into the hexane
solution, the polyacene derivatives of examples 1 and 3 were dissolved
into the hexane solution and became deep blue solutions. Also, the
polyacene derivative of the inventive example 4 of which number of the
substituents is less than that of the polyacene derivative of example 2
by four was dissolved into the hexane solution. From the above-mentioned
results, the length of the substituent is important rather than the
number of the substituent and it became clear that the substituent having
the length longer than that of the propyl group is more effective for
improving solubility of solvent.

Example 5

[0245]Example 5 also is a modified example of example 1. A chemical
formula of an organic semiconductor material of example 5 is shown as
follows.

##STR00036##

[0246]The organic semiconductor material according to example 5 is made of
a polyacene derivative shown by the above-described general formula (1).
In the general formula (1), R1, R2, R3, R4, R5,
R6, R7, R8, R9 and RIO are respectively
substituents which will follow. That is, the organic semiconductor
material of example 5 is 2-cyano-1,4,6,13-tetrabutyl-8,9,10,11-tetraethyl
pentacene.

[0247]R1: aliphatic hydrocarbon group (concretely, butyl group)

[0248]R2: cyano group

[0249]R3: hydrogen atom

[0250]R4: aliphatic hydrocarbon group (concretely, butyl group)

[0251]R5: aliphatic hydrocarbon group (concretely, butyl group)

[0252]R6: aliphatic hydrocarbon group (concretely, ethyl group)

[0253]R7: aliphatic hydrocarbon group (concretely, ethyl group)

[0254]R8: aliphatic hydrocarbon group (concretely, ethyl group)

[0255]R9: aliphatic hydrocarbon group (concretely, ethyl group)

[0256]R10: aliphatic hydrocarbon group (concretely, ethyl group)

[0257]Alternatively, the organic semiconductor material according to the
inventive example 5 is made of a polyacene derivative shown by the
above-described general formula (2). RI, R2, R3, R4,
R5, R6, R7 and R8 in the general formula (2) are the
following substituents, respectively. Also in the inventive example 5, an
equality of n=4 is satisfied.

[0258]R1: aliphatic hydrocarbon group (concretely, butyl group)

[0259]R2: cyano group

[0260]R3: hydrogen atom

[0261]R4: aliphatic hydrocarbon group (concretely, butyl group)

[0262]R51: hydrogen atom

[0263]R52: aliphatic hydrocarbon group (concretely, butyl group)

[0264]R53: hydrogen atom

[0265]R54: aliphatic hydrocarbon group (concretely, ethyl group)

[0266]R6: aliphatic hydrocarbon group (concretely, ethyl group)

[0267]R7: aliphatic hydrocarbon group (concretely, ethyl group)

[0268]R81: aliphatic hydrocarbon group (concretely, ethyl group)

[0269]R82: hydrogen atom

[0270]R83: aliphatic hydrocarbon group (concretely, butyl group)

[0271]R84: hydrogen atom

[0272]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using the chloroform solution (concentration: 5
g/lit.) of the organic semiconductor material of example 5 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 1.7×10-3
cm2 V-1 second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

Example 6

[0273]Example 6 relates to the organic semiconductor materials, the
organic semiconductor thin films and the organic semiconductor devices
according to the second and third aspects of the present invention. A
chemical formula of the organic semiconductor material according to
example 6 is shown as follows.

##STR00037##

[0274]The organic semiconductor material according to example 6 is made of
a polyacene derivative shown by the following general formula (3). In the
general formula (3), R1, R2, R3, R4, R5 and
R6 are respectively substituents propyl groups.

##STR00038##

[0275]Alternatively, the organic semiconductor material according to
example 6 is made of the polyacene derivative shown by the
above-described general formula (2). R1r R2, R3, R4,
R5, R6, R7 and R8 in the general formula (2) are
respectively the following substituents. In example 6, an equality of n=3
is satisfied.

[0276]R1: aliphatic hydrocarbon group (concretely, propyl group)

[0277]R2: aliphatic hydrocarbon group (concretely, propyl group)

[0278]R3: aliphatic hydrocarbon group (concretely, propyl group)

[0279]R4: aliphatic hydrocarbon group (concretely, propyl group)

[0280]R51: hydrogen carbon

[0281]R52: aliphatic hydrocarbon group (concretely, propyl group)

[0282]R53: hydrogen carbon

[0283]R6: hydrogen carbon

[0284]R7: hydrogen carbon

[0285]R81: hydrogen carbon

[0286]R82: aliphatic hydrocarbon group (concretely, propyl group)

[0287]R83: hydrogen carbon

[0288]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using a mesitylene solution (concentration: 5
g/lit.) of the organic semiconductor material of example 6 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 0.01 cm2
V-1 second-1 was obtained as mobility in the saturated region
at that time depending on conditions of the spin coating and the like.

Example 7

[0289]Example 7 is a modified example of example 6. A chemical formula of
the organic semiconductor material according to example 7 is shown as
follows.

##STR00039##

[0290]The organic semiconductor material according to example 7 is made of
a polyacene derivative shown by the above-described general formula (3).
R1, R4, R5 and R6 in the general formula (3) are
respectively propyl groups and R2 and R3 are respectively
methoxycarbonyl group.

[0291]Alternatively, the organic semiconductor material according to
example 7 is made of the polyacene derivative shown by the
above-described general formula (2). R1, R2, R3, R4,
R5, R6, R7 and R8 in the general formula (2) are
respectively the following substituents. Also in the inventive example 6,
an equality of n=3 is satisfied.

[0292]R1: aliphatic hydrocarbon group (concretely, propyl group)

[0293]R2: carbonyl group (concretely, methoxycarbonyl group)

[0294]R3: carbonyl group (concretely, methoxycarbonyl group)

[0295]R4: aliphatic hydrocarbon group (concretely, propyl group)

[0296]R51: hydrogen atom

[0297]R52: aliphatic hydrocarbon group (concretely, propyl group)

[0298]R53: hydrogen atom

[0299]R6: hydrogen atom

[0300]R7: hydrogen atom

[0301]R81: hydrogen atom

[0302]R82: aliphatic hydrocarbon group (concretely, propyl group)

[0303]R83: hydrogen atom

[0304]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using a toluene solution (concentration: 5
g/lit.) of the organic semiconductor material of example 7 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 2.0×105
cm2V-1. second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

Example 8

[0305]The inventive example 8 also is a modified example of example 6. A
chemical formula of the organic semiconductor material according to
example 8 is shown as follows.

##STR00040##

[0306]The organic semiconductor material according to example 8 is made of
a polyacene derivative shown by the above-described general formula (3).
R1r R2, R3 and R4 in the general formula (3) are
respectively ethyl groups and R5 and R6 are respectively butyl
groups.

[0307]Alternatively, the organic semiconductor material according to
example 8 is made of the polyacene derivative shown by the
above-described general formula (2). R1r R2, R3, R4,
R5, R6, R7 and R8 in the general formula (2) are
respectively the following substituents. Also in the 8, an equality of
n=3 is satisfied.

[0308]R1: aliphatic hydrocarbon group (concretely, ethyl group)

[0309]R2: aliphatic hydrocarbon group (concretely, ethyl group)

[0310]R3: aliphatic hydrocarbon group (concretely, ethyl group)

[0311]R4: aliphatic hydrocarbon group (concretely, ethyl group)

[0312]R5: hydrogen atom

[0313]R52: aliphatic hydrocarbon group (concretely, butyl group)

[0314]R53: hydrogen atom

[0315]R6: hydrogen atom

[0316]R7: hydrogen atom

[0317]R81: hydrogen atom

[0318]R82: aliphatic hydrocarbon group (concretely, butyl group)

[0319]R83: hydrogen atom

[0320]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using a mesitylene solution (concentration: 5
g/lit.) of the organic semiconductor material of example 8 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 2.0×105
cm2 V-1 second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

Example 9

[0321]Example 9 also is a modified example of example 6. A chemical
formula of the organic semiconductor material according to example 9 is
shown as follows.

##STR00041##

[0322]The organic semiconductor material according to example 9 is made of
a polyacene derivative shown by the above-described general formula (3).
R1, R2, R3 and R4 in the general formula (3) are
respectively hydrogen atoms and R5 and R6 are respectively
butyl groups.

[0323]Alternatively, the organic semiconductor material according to
example 9 is made of the polyacene derivative shown by the
above-described general formula (2). R1r R2, R3, R4,
R5, R6, R7 and R8 in the general formula (2) are
respectively the following substituents. Also in the inventive example 9,
an equality of n=3 is satisfied.

[0324]R1: hydrogen atom

[0325]R2: hydrogen atom

[0326]R3: hydrogen atom

[0327]R4: hydrogen atom

[0328]R5: hydrogen atom

[0329]R52 aliphatic hydrocarbon group (concretely, butyl group)

[0330]R53: hydrogen atom

[0331]R6: hydrogen atom

[0332]R7: hydrogen atom

[0333]R81: hydrogen atom

[0334]R82: aliphatic hydrocarbon group (concretely, butyl group)

[0335]R83: hydrogen atom

[0336]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using a chloroform solution (concentration: 5
g/lit.) of the organic semiconductor material of example 8 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 2.0×109
cm2V1 second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

Example 10

[0337]Example 10 also is a modified example of the inventive example 6. A
chemical formula of the organic semiconductor material according to the
inventive example 10 is shown as follows.

##STR00042##

[0338]The organic semiconductor material according to example 10 is made
of a polyacene derivative shown by the above-described general formula
(3). R1, R2, R3 and R4 in the general formula (3) are
respectively hydrogen atoms and R5 and R6 are respectively
propyl group.

[0339]Alternatively, the organic semiconductor material according to
example 10 is made of the polyacene derivative shown by the
above-described general formula (2). R1, R2, R3, R4,
R5, R6, R7 and R8 in the general formula (2) are
respectively the following substituents. Also in example 10, an equality
of n=3 is satisfied.

[0340]R1: hydrogen atom

[0341]R2: hydrogen atom

[0342]R3: hydrogen atom

[0343]R4: hydrogen atom

[0344]R51: hydrogen atom

[0345]R52: aliphatic hydrocarbon group (concretely, propyl group)

[0346]R53: hydrogen atom

[0347]R6: hydrogen atom

[0348]R7: hydrogen atom

[0349]R81: hydrogen atom

[0350]R82: aliphatic hydrocarbon group (concretely, propyl group)

[0351]R83: hydrogen atom

[0352]Operations of a test product (see a schematic fragmentary
cross-sectional view of FIG. 3) of an organic field-effect transistor
having a channel forming region formed based on the coating process such
as a spin coating method using a mesitylene solution (concentration: 5
g/lit.) of the organic semiconductor material of example 7 at room
temperature were confirmed. As a result, gate modulation could be
confirmed and it could be confirmed that the organic semiconductor thin
film has played a role of the channel forming region. 2.0×10-9
cm2V1 second-1 was obtained as mobility in the saturated
region at that time depending on conditions of the spin coating and the
like.

[0353]While the present invention has been described according to the
embodiments above, it should be appreciated that the present invention is
not limited to those preferred embodiments. That is, structures,
arrangements, manufacturing conditions and manufacturing methods of the
organic field-effect transistors according to the present invention have
been described and shown by way of example and it is needless to say that
these can be changed freely. When the organic field-effect transistor
(FET) according to the present invention is applied to and used by a
display apparatus and various kinds of electronic device, it can be
formed as a monolithic integrated circuit in which many FETs are
integrated in the substrate and the supporting member or each FET may be
cut to provide individual parts, which can be used as discrete
assemblies.

[0354]A polyacene compound is a compound in which benzene rings are bonded
in a straight fashion and a polyacene compound without substituent has
properties in which it becomes more difficult to be dissolved into an
organic solvent in accordance with the increase of the number of benzene
rings. In particular, a polyacene greater than a pentacene having five
benzene rings bonded loses solubility relative to almost all of organic
solvents and it is difficult to form a uniform film based on a suitable
method such as a spin coating method. If possible, then it is unavoidable
that the organic solvent available in this case is limited to extremely
limited organic solvents and temperature conditions. However, according
to the present application, since the organic semiconductor material
consists of the polyacene derivatives into which the substituents were
introduced, it is possible to improve solubility of the organic
semiconductor material relative to various kinds of organic solvents.
Hence, it is possible to form/deposit a uniform film based on the coating
process such as the spin coating method. As earlier noted, since
2,3,9,10-tetramethyl pentacene and 2,3-dimethyl pentacene are known well,
it has been reported that, if 1,2-dichlorobenzene with high
extractability is in use, the organic semiconductor material is slightly
dissolved in the state in which it is warmed. Therefore, it can be
gathered from this report that introduction of substituents into the
polyacene derivatives in the organic semiconductor material considerably
affects solubility of the organic semiconductor materials into the
organic solvents.

[0355]Also, according to the present application, not only the solubility
of the organic semiconductor material with respect to the organic solvent
can be improved but also, oxidation resistance can be improved and
control of packing rules (herringbone structure/stack structure), in the
organic semiconductor thin film and crystallinity can be improved by the
introduction of substituents. Further, by using the polyacene derivative
in which a substituent with a polarity and a substituent without polarity
are introduced into desired positions, it becomes possible to control
orientation and inclination of the organic semiconductor material
relative to a base material (underlying layer or substrate). Also, it
becomes possible to carry out patterning on the organic semiconductor
material by bonding the polyacene derivative to functional groups
introduced into desired positions of a base material (underlying layer or
substrate). Further, the polyacene derivatives have a possibility that
they will change their conductivity types depending on the substituents.
It is known that, while ordinary pentacene without substituent behaves as
a p-type semiconductor, pentacene in which all hydrogen atoms are
replaced with fluorine atoms acts as an n-type semiconductor. Then,
according to the present invention, since the organic semiconductor
material is formed as the polyacene derivative into which the
substituents are introduced, electron transition energy is changed with
the result that it becomes possible to control a conductivity type.

[0356]It should be understood by those skilled in the art that various
modifications, combinations, sub-combinations and alterations may occur
depending on design requirements and other factors insofar as they are
within the scope of the appended claims or the equivalents thereof.

Patent applications by Ken-Ichiro Kanno, Hokkaido JP

Patent applications by Noriyuki Kawashima, Kanagawa JP

Patent applications by Takahiro Ohe, Tokyo JP

Patent applications by Tamotsu Takahashi, Hokkaido JP

Patent applications by National University Corporation Hokkaido University